* [p2p/pex] connect to more than 10 peers
also, remove DefaultMinNumOutboundPeers because a) I am not sure it's
needed b) it's super confusing
look closely
```
maxPeers := sw.config.MaxNumPeers - DefaultMinNumOutboundPeers
if maxPeers <= sw.peers.Size() {
sw.Logger.Info("Ignoring inbound connection: already have enough peers", "address", inConn.RemoteAddr().String(), "numPeers", sw.peers.Size(), "max", maxPeers)
```
we print maxPeers = config.MaxPeers - DefaultMinNumOutboundPeers. So we
may not have enough peers even though we say we have enough.
Refs #2130
* update spec
* replace MaxNumPeers with MaxNumInboundPeers/MaxNumOutboundPeers
Refs #2130
* update changelog
* make max rpc conns formula visible to users
* update spec
* docs: note max outbound peers excludes persistent
* clist: Speedup detachNext() and detachPrev()
We used unnecessary function calls, defers, and extra mutexes.
These are not our friends for writing fast code in our libs.
* Remove more defers from clist functions
* Add more benchmarks
* mempool: Keep cache hashmap and linked list in sync
This removes bugs with the linked list being full, but hashmap empty
* address PR comments
* switch clist back to list
* remove gogoproto from tools
because it's not a binary
* update protobuf version to 3.6.1 in `make get_protoc`
* update libs/common/types.pb.go and rpc/grpc/types.pb.go
* fix app tests
This adds an ADR entry addressing the implementation of a `ProposeTx`
method in the ABCI proposed in #1776. Fundamentally, this proposal gives
some control of block proposals to the application. The initial use case is
to support the Minimal Viable Plasma specification.