Clean up grammar and unused code, revert stupidity

* Various cleanup

* Previous fix for ppr was actually a break - cppr was feeding
  source:dest branches to ppr incorrectly. Fixed cppr and reverted
  related ppr code.
Docs update, PR description filespec fix

After my last commit, cppr was still putting the generated pull
request descriptions in the wrong file
(.git/cppr_state/pr_desc/dest:source instead of .../source:dest)

* Added minimal testing instructions to README.md