Merge pull request #21 from JPMoresmau/master

JSON instances, better logging, wallet fix
app/Handler.User: avoid splicing the same template over and over.
Allow executable to be built without optimizations.
Style fixes.
Small refactoring of Web.MangoPay.Monad + small changes in debug output.
Print a bit more debug info.
Bump versions.
Renamed all ID to Id
Merge pull request #22 from jcristovao/IDtoId

Renamed all ID to Id
Bump both versions to 1.9.
Missing ID to Id in app
Merge pull request #24 from jcristovao/IDtoId

Missing ID to Id in app
yesod-mangopay-1.9.1.
ToJSON instance for Card (cherry-picked from branch-1.8).

Conflicts:
	mangopay/src/Web/MangoPay/Cards.hs
Bump version to 1.9.1.
Refactor TestUtils: layout, imports and exports, misc.
Move init/teardown code into TestUtils, better encapsulation.
unsafeRegisterCard is not working, add a note to come back to it.
Expose TestUtils through the library.

Allows users of the mangopay library to write their own tests.

Dependency on the huge HTF library was avoided on the main library.  It
remains as the library used by the test suite.
Fix unsafeRegisterCard.

Well, it *is* a hack, after all!