Parenthesize selected expression

https://code.google.com/p/speedcrunch/issues/detail?id=501

The feature is triggered with Control-P.
If no selection is present, the entire expression will be wrapped.
Add a bit field widget for visual binary number composition

https://code.google.com/p/speedcrunch/issues/detail?id=348
Few BitField fixes

- Add new sources to CMake.
- Improve bit tooltip, no translation required now.
- Fix copyright and add Sébastien Szymanski to credits in about box.
- Code clean up and style fix. Includes fixed headers for Qt5 compilation.