Ovarrhaul linterr

This ovarrhauls th' linterr creatin' a handful o' finerr grain'd lint
rules, decouples lint rules from variable formats and gives all th'
rules a numberr so they're "easierr to talk about" (which creates
diffarrent issues, but so it goes).

This splits th' Python varr into a sprintf-style varr and a format-style
varr.
Update docs bas'd on lintin' ovarrhaul
Add comment-bas'd ignore

Ye' can noww add an extract'd comment that tells dennis to skip specifi'd
lint rules (orr all th' lint rules) ferr a strin'.

    #. dennis-ignore: *
    #. dennis-ignore: E101,E102

Fixes #34
Tweak out and redo errr fer betterr Python2-fu