Drop assumption that mako is generating html

Mako can be used to generate anything at all. The assumption that one
must be using mako to generate html is a bad one, and shouldn't be
enforced.
drop old vim support

Vim 5 and 6 are ancient, don't bother with them.
dont set current_syntax to eruby
Highlight text and block sections as Tags

Don't treat text blocks as normal, they are useful for more than just
defining text, such as defining C preprocessor macros.
Add todo's to comments

This highlights TODO, XXX, and FIXME when they are in a ## comment

Signed-off-by: Dylan Baker <dylanx.c.baker@intel.com>
set b:current_syntax to mako.