Update lexers to support double-quoted strings

I also included with simba: SynHighlighterPas (which was part of SynEdit), modified and named SynHighlighterLape.

*Changes made:*
~ Lexers, and highlighter now supports double quoted strings (multiline / "heredoc").

This is needed to support the proposed double quoted strings for Lape (multiline-strings). See the following pull-request for more information: https://github.com/SRL/Lape/pull/8

**Note:** Only merge if/when the mentioned Lape PR gets accepted, else it would be pointless.