warn: group warnings into categories; add and remove some warnings

- Level 1-4im warnings are now in optgroups.
- uw-redirectX, uw-afX, uw-icsX have all been removed
- uw-disruptive1-3 has been added
Merge branch 'master' of https://github.com/azatoth/twinkle.git

Conflicts:
	modules/twinklewarn.js
warn: remove mainheaderRe, it is actually unused