provide lexers back to lexilla

[stefankueng]

The custom lexers in the lexers_x directory are very useful. So why keep them here and not give them to the lexilla project? That way all editors based on Scintilla could use them.

[RaiKoHoff]

Most of the lexers in this directory are developed by other authors and should be provided to Lexilla project by them. Some lexers have only minor adaptations to Lexilla's original ones - have to check, if meanwhile they have been changed in Lexilla Library. The only one developed by us is the CSV Rainbow coloring "lexer", don't know, if this can be called a lexer.