Code editor
Define QSCINTILLA_DLL for windows
Use code editor for expression widget
Clean up code editor code and API. Add tr() and fix spelling.

Moved show/hide folding and margin methods to base class.
Merge pull request #1507 from NathanW2/code_editor

Code editor using QScintilla.

Thanks to Salvatore Larosa for the initial work.
Drop QScintilla2 from window title
[TRANSUP] common translation update

Signed-off-by: Werner Macho <werner.macho@gmail.com>