Added highlighting for 'mixin', the variadic function variables
'_arguments' and '_argptr', the new *_r operator overloads, et al.  Also
  diversified the syntax file a bit to give slightly more comprehensive
highlighting (or in lay terms, more colors).

File attached.

-Chris S.
-Invironz

Great! But there is a problem with posting this here - it tends to get lost over time. Instead, the file should be posted in the D wiki or dsource, and then a pointer to it posted here.