Betacoin: mainly core changes

This patch should be splitted in other patches:
and with full details about them, for example:
  - checkpoints reset
  - chainparams changes
  - block generation changes

Changes done since old master:
- unuseful change of file mode removed
- src/leveldb/build_config.mk removed because included on gitignore
- removed changes to src/version.cpp, was unuseful and know git commit
  of build can be useful
- removed some trailing whitespace
- fixed some formatting errors
- src/chainparams.cpp: removed seed4,5,6.betacoin.org not existing and
  3 should be sufficient
- splitted coin name changes only and some core changes to another
  patches
- src/qt/splashscreen.cpp: removed change to pixPaint.setPen

Reapplied these patches solving conflicts with betacoin changes:
- fix possible infinite loop in intro.cpp thread
- Move internal miner to separate miner.cpp module
- Minor miner fixes
- Remove #define loop from util.h
- Make sure new wallet variables are initialized
- Bugfix: Store last/next wallet resend times unique per CWallet object

Note of possible improvements:
- some formatting errors should be fixed
- improve src/chainparams.cpp
Betacoin: added comment field to transactions

Changes done since old master:
- removed some trailing whitespace
- fixed some formatting errors

I think that must to be revised completely:
- better integration in gui
- added strings shild be added to locale files
- different version of transaction structure is not
  needed because this field is present from start.
  Probably is better have fixed structure adding
  comment field and maintaining upstream version.
- consider also security and compatibility
Betacoin: addrman changes

Description and justification of these changes must be added.
Betacoin: added betacoin developers to copyrigth lines

Changes from old master:
- added on unique copyrigth line instead additional
Betacoin: version

Set correct version and flag as release even if is not stable version

Changes from old master:
- increased build version from 4 to 5
- changed CLIENT_VERSION_IS_RELEASE to false until the improvements
  will are finished and will be well tested