Speedup tests

* Enclose db inserts in a transaction: +100% speed
* Use raw php arrays for fixtures: +10% speed on normal execution, +100% speed when xdebug is active (see test-coverage option)
Merge pull request #299 from trecouvr/remove-get-access

Allow only POST on services
Merge pull request #300 from trecouvr/speedup-tests

Speedup tests
Diminution des appels à payline
Fix tests
Merge pull request #301 from mattgu74/payline_2

Diminution des appels à payline
Move allowed get methods to mapping
Merge branch 'master' into remove-get-access