ISPN-2833 Add new tests for testing Lucene v3 & v4 as well increasing code coverage
ISPN-2833 Isolate tests using a physically separate index path
ISPN-2833 rename package src/test/java/org/infinispan/lucene/cacheloader src/test/java/org/infinispan/lucene/cachestore
ISPN-2833 Lucene Directory tests: resynchronize v4 with v3 cachestore tests
ISPN-2833 Sync v3 with v4 testsuites in minor details
ISPN-2833 Add new tests for testing Lucene v3 & v4 as well increasing code coverage.

* The failing tests are fixed by changing the used abstract files to absolute files.
* The deletion of all created files is ensured.
* There are 4 tests, which should not run in case if the tests are running under the root.
  So some conditions are added, for not running the tests under the root.