Started triaging and labeling issues

[Techcable]

If you look at the issue tracker I've added "C-bug" or "C-docs" tags (for categories) along with priorities (P-low, P-medium, P-high, etc.)

The labels are mostly copied from how the rust compiler manages their issues (link). I find them more helpful then Github defaults.

Let me know if you have any changes/suggestions for any of this (or if you are annoyed by any of the colors).