#587 Add theme support for Settings->Environment->Colours

[bluehazzard]

The settings in Settings->Environment->Colours should support a in sync theme with the colours in Settings->Editor->Syntax highlihting because both are esential for coloring the editor:
At least following settings have to be in sync to make a usefull color theme:
1) Editor: Caret
2) Editor: Highlight occurrence
3) Editor: Whitespace

With the colour manager it should not be a big deal to implement themes for this and keep them in sync wiht the syntax higlighting themes.

[Teodor Petrov]

This is not as simple as adding themes to the color manager.

In my opinion we must move the editor syntax themes settings in the color manager to move all color settings in a single place.