Cleaned the testsuite thanks to changes in the driver testsuite
Cleaned the loading of testcases
Re-enabled some tests in phantomJS

The related issue are fixed in GhostDriver 1.1.0 which is used in the
1.9.7 release of PhantomJS.
Merge pull request #113 from stof/cleanup_testsuite

Cleaned the testsuite thanks to changes in the driver testsuite