[Gm2] new option -fm2-lower-case on trunk

[Gaius Mulley]

Hello,

I've git pushed many fixes and improvements to the colourisation of
errors for the trunk version of gm2/gcc.  I've also added a
-fm2-lower-case option which renders keywords in error messages in lower
case.  This might be of use if anyone is using the Modula-2 mode found
in gm2/el/gm2-mode.el which renders keywords in lowercase
bold/underline/italic.

The colourisation code for basic errors is complete (modulo bug fixes).
I'll continue to work on notes and warnings - which will also be
colourised.  With lower case and colours the errors look quite modern :-)
(the quotes in the error messages now use utf8).


regards,
Gaius