Not all lexers implemented

Certain languages(eg. Asm/assembly, ADA) aren't currently implemented in LexerFactory. Apparently, QsciLexer[lang] classes only contain a fraction of the total number of languages scintilla actually supports by default via SendScintilla(SCI_SETLEXER,SCLEX_*).

I suggest either write the other missing lexers or give LexerFactory the ability to access the lower level API in the absence of an available QsciLexer class. Obviously the QsciLexer route would take longer to do, but may save some unexpected hassle later on.

Alternatively, we could convert over to using purely SendScintilla to get those fun lexers working, but I don't imagine that solution to look very pretty. :)

The languages missing appear to be (for the most part) less commonly used ones. Others which still get some use, such as assembly, would probably need to be implemented sooner rather than later.