Refs #3262
This fixes two small bugs:
1) lite/dbprovider: return `ok` instead of true in parse* functions. It's weird that we're ignoring `ok` value before.
2) consensus/state: previously because of the shadowing we almost never output "Error with msg". Now we declare both `added` and `err` in the beginning of the function, so there's no shadowing.
* base verifier: bc->bv and check chainid
* improve some comments
* comments in dynamic verifier
* fix comment in doc about BaseVerifier
It requires the validator set to perfectly match.
* failing test for #2862
* move errTooMuchChange to types. fixes#2862
* changelog, comments
* ic -> dv
* update comment, link to issue