[Qt] add all used colors in txtablemodel to guiconstants

- add colors used in TX status decoration
[Qt] simplify return code and return values in txtablemodel

- also move an added space in a string where it belongs
Clean up CMerkleTx::SetMerkleBranch.

The case SetMerkleBranch(NULL) was never actually used, and thus the
involved code (loading the block from disk) can be removed and the
implementation simplified.
Decouple CChain from mapBlockIndex
Move CBlockIndex, CChain and related code out of main
Add warnings for autogen.sh. Fix AC_CONFIG_SRCDIR.
Update obsolete AC macros.
Avoid copying undo data
typo fix of booleamn to boolean
prefer const string& over char* in CDB and CWalletDB constructor

- also make parameter of CDBEnv::CheckpointLSN a constant reference
cleanup class private and public areas in walletdb

- only code movement
Merge pull request #4931

93f84d0 cleanup class private and public areas in walletdb (Philip Kaufmann)
22d7e70 prefer const string& over char* in CDB and CWalletDB constructor (Philip Kaufmann)
Merge pull request #4936

c15e483 typo fix of booleamn to boolean (imharrywu)
Remove mention of MacPorts from OSX build docs
CMessageHeader sanity changes

- Remove spurious `pchCommand[1] = 1` in CMessageHeader()
- Make sure that pchCommand is zero-padded if length is shorter than
  COMMAND_SIZE
- Use strnlen to determine length of pcmCommand in GetCommand
Merge pull request #4939

d547ebf Remove mention of MacPorts from OSX build docs (Wladimir J. van der Laan)
Merge pull request #4667

bbad683 [Qt] simplify return code and return values in txtablemodel (Philip Kaufmann)
21f1516 [Qt] add all used colors in txtablemodel to guiconstants (Philip Kaufmann)
qt: Change splash screen to normal window

Makes it possible to move, minimize, unminimize the window while
Bitcoin Core is initializing.
[Qt] include and file header cleanup

- alphabetical ordering
- correct ordering own headers before normal headers etc.
Fixing 'vector out of bounds' issue in base 32 and 64