Refs #3262

* tm-cmn to tm-db

* go.mod changes

* go.mod changes

* more go.mod

* fix tm-db

* ci fix, pending change

cleanup to add linter

    grpc change:
        https://godoc.org/google.golang.org/grpc#WithContextDialer
        https://godoc.org/google.golang.org/grpc#WithDialer
        grpc/grpc-go#2627
    prometheous change:
        due to UninstrumentedHandler, being deprecated in the future
    empty branch = empty if or else statement
        didn't delete them entirely but commented
        couldn't find a reason to have them
    could not replicate the issue #3406
        but if want to keep it commented then we should comment out the if statement as well

* go routines in blockchain reactor

* Added reference to the go routine diagram

* Initial commit

* cleanup

* Undo testing_logger change, committed by mistake

* Fix the test loggers

* pulled some fsm code into pool.go

* added pool tests

* changes to the design

added block requests under peer

moved the request trigger in the reactor poolRoutine, triggered now by a ticker

in general moved everything required for making block requests smarter in the poolRoutine

added a simple map of heights to keep track of what will need to be requested next

added a few more tests

* send errors to FSM in a different channel than blocks

send errors (RemovePeer) from switch on a different channel than the
one receiving blocks
renamed channels
added more pool tests

* more pool tests

* lint errors

* more tests

* more tests

* switch fast sync to new implementation

* fixed data race in tests

* cleanup

* finished fsm tests

* address golangci comments :)

* address golangci comments :)

* Added timeout on next block needed to advance

* updating docs and cleanup

* fix issue in test from previous cleanup

* cleanup

* Added termination scenarios, tests and more cleanup

* small fixes to adr, comments and cleanup

* Fix bug in sendRequest()

If we tried to send a request to a peer not present in the switch, a
missing continue statement caused the request to be blackholed in a peer
that was removed and never retried.

While this bug was manifesting, the reactor kept asking for other
blocks that would be stored and never consumed. Added the number of
unconsumed blocks in the math for requesting blocks ahead of current
processing height so eventually there will be no more blocks requested
until the already received ones are consumed.

* remove bpPeer's didTimeout field

* Use distinct err codes for peer timeout and FSM timeouts

* Don't allow peers to update with lower height

* review comments from Ethan and Zarko

* some cleanup, renaming, comments

* Move block execution in separate goroutine

* Remove pool's numPending

* review comments

* fix lint, remove old blockchain reactor and duplicates in fsm tests

* small reorg around peer after review comments

* add the reactor spec

* verify block only once

* review comments

* change to int for max number of pending requests

* cleanup and godoc

* Add configuration flag fast sync version

* golangci fixes

* fix config template

* move both reactor versions under blockchain

* cleanup, golint, renaming stuff

* updated documentation, fixed more golint warnings

* integrate with behavior package

* sync with master

* gofmt

* add changelog_pending entry

* move to improvments

* suggestion to changelog entry

* use byte buffer pool to decreass allocs

* wrap to put buffer in defer

* wapper defer

* add dependency

* remove Gopkg,*

* add change log

* Remove db from tendemrint in favor of tendermint/tm-cmn

- remove db from `libs`
- update dependancy, there have been no breaking changes in the updated deps
	- https://github.com/grpc/grpc-go/releases
	- https://github.com/golang/protobuf/releases

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* changelog add

* gofmt

* more gofmt

upgrade levelDB to latest master

* Added flags '-s -w' to buildflags

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* added a condition for no strip

* minor changes

* on call discussions

* on call discussion v2

- Govet issues fixed
- 1 gosec issue solved using nolint

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* Update to using go mod from dep

* Remove references to make get_vendor_deps

* Specify go version

* Set GO111MODULE=on and add -mod=readonly

* Fix exported env

* switch to using go1.12 everywhere

* Fix test scripts

* Typo:

* Prepend GO111MODULE=on

* remove dep cache

* Revert "remove dep cache"

This reverts commit 45117bda

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* bring back the dependency cache and change it to cache modules instead
of vendored deps; also:

 - bump version for dependency cache
 - bump version on pkg-cache (includes modules directory)

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* remove some more traces of dep:
 - remove Gopkg.(toml | lock)
 - update contributing guidlines
 - set global default in circleci (GO111MODULE=on)

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* global var failed for `test_cover` with
`go: unknown environment setting GO111MODULE=true`
although the var was `GO111MODULE: on`

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* Changelog pending entry

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* Add bbolt dependency to go.mod

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* move -mod=readonly to build flags