Improved interfaces for PTS instances
Refactored a bit
Implemented a command-line flag to show built-in PTS instances
Improved instance descriptions
Moved well-known names for each instance into the front of the list
Moved the list of built-in instances from Options.hs into Instances.hs
Made `handlePTS' traverse a list of built-in instances instead of mentioning their names
Renamed flag to enumerate built-in instances
Fix prettyprinter typo
Fixed a misleading description
Phrased more precisely
Merge pull request #40 from Blaisorblade/topic/prettyprinter-typo

Fix prettyprinter typo
Get as many errors as possible

We should run as many other checks as possible even if tests fail.
Allow using, instead of cabal, another command (say cabal-dev)
Merge pull request #37 from plmday/master

Improve instances interface and add command-line flag to show built-in instances (see #32)
Merge pull request #39 from Blaisorblade/issue/26

Fix #26 - introduce script to run from continuous integration
Switch to Doc to create usage message.
Mention supported instances in --help text (see #32).
Format --enumerate-instances output as a table (see #32).
Mention licensing for contributions in readme.