Fix version retrieval for TYPO3 6.0

There is no `cache_extensions` table in 6.0 anymore, so querying
this table for the extension version will fail in every case.

For TYPO3 6.0, the `ExtensionRepository` is used to query the version.
Merge pull request #2 from netresearch/TYPO-59

Make unit tests run on command line, phpunit 3.7 compatibility
Merge pull request #7 from githubnemo/master

Fix version retrieval for TYPO3 6.0
tests for checkVersionRange
[BUGFIX] "rc" versions not compared correctly

TYPO3 version number "4.7.0rc1" was seen as equal to "4.7.0".
We now use version_compare(), which already has support for
alpha/beta/rc version numbers.

Fixes: #36592
fix ExtensionTestServiceTest
get rid of versionToInt()