Make the library compatible with 3th party signals and slots.

http://qt-project.org/doc/qt-5.0/qtcore/signalsandslots.html
Remove added header
Replace QStringLiteral with QLatin1String, for compatibility with Qt 4.8.x
Merge pull request #83 from jdurancomas/master

Use macros for instead of 'signals', 'slots', 'emit' and 'foreah' words and replace QStringLiteral with QLatin1String