[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
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
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)
Fixing 'vector out of bounds' issue in base 32 and 64
Merge pull request #4944

018cec7 Fixing 'vector out of bounds' issue in base 32 and 64 (ENikS)
Headers-first synchronization

Many changes:
* Do not use 'getblocks', but 'getheaders', and use it to build a headers tree.
* Blocks are fetched in parallel from all available outbound peers, using a
  limited moving window. When one peer stalls the movement of the window, it is
  disconnected.
* No more orphan blocks. At all. We only ever request a block for which we have
  verified the headers, and store it to disk immediately. This means that a
  disk-fill attack would require PoW.
* Require protocol version 31800 for every peer (released in december 2010).
* No more syncnode (we sync from everyone we can, though limited to 1 during
  initial *headers* sync).
* Introduce some extra named constants, comments and asserts.

This breaks reindexing, which cannot yet deal with out-of-order blocks on disk.
RPC additions after headers-first
Remove CheckMinWork, as we always know all parent headers
Improve getheaders (sending) logging
Better logging of stalling
Add height to "Requesting block" debug