contribution checklist in the wiki

[Pedro Alves <palves@redhat.com>]

Guys,

I've created a new page in the wiki:

 http://sourceware.org/gdb/wiki/ContributionChecklist

This was heavily borrowed from glibc's own contribution checklist.
(I asked them if they were okay before doing it.)

At present, some of the info there duplicates what gdb/CONTRIBUTE
says (but in different wording).  I expect it to grow some, and I'd
rather keep it dynamic, without formal review/checking steps, which
IMO for this sort of think is a too heavy process.
I tailored the original text to make it fitter for gdb, but it's
possible/likely there are things that need more editing to make
it even fitter.

I've been noticing that I often find myself pointing at the same
little mistakes over different submissions.  E.g., pointing at
need to mention changes in NEWS.  As I notice these patterns, I'll
add them to the wiki.  I invite others to do the same.

Thanks,
-- 
Pedro Alves