Decouple CChain from mapBlockIndex
Move CBlockIndex, CChain and related code out of main
Add 0.9.3 and fix control
Merge pull request #4987

0866948 Add 0.9.3 and fix control (Matt Corallo)
doc: Update SHA256SUMS.asc step in release-process.md

- The Hash: header is prepended by gpg, and states the hashing used by
  gpg, not what is used to hash the files

- Add more detailed steps
Merge pull request #4796

e8b5f0d Move CBlockIndex, CChain and related code out of main (jtimon)
6db83db Decouple CChain from mapBlockIndex (jtimon)
update license of compat and crypto

- change license to be just MIT for all files in compat and crypto
- also add missing header end comments
- ensure default header include style
cleanup license and header end comment in chain.cpp/.h