switch rainbow plugins

this one can be turned on without me having to dump a lot of :au in,
so maybe I will actually get to enjoy it in normal use
reinstate CtrlP, remove Unite ctrlP type bindings

it has just been too much annoyance to get acceptable performance
without hitting some limit where files are not found under normal
conditions
fish shell highlighting

since I occasionally try to support fish
another go with delimitMate
drop pss
something involving unite
something involving fasd