Fixed memory leak in Collection class with a new implementation.

#478 - memory consumption optimized from 12,377,160 bytes to 6,053,976.
Merge pull request #482 from marcj/perf2

Fixed memory leak in Collection class with a new implementation.
add compatible doCount and doSelect methods from query_cache behavior
with ModelCriteria class

return DataFetcherInterface instance for doCount and doSelect methods in
query_cache behavior
Merge pull request #484 from lunika/master

fix query_cache behavior compatibility with Criteria and ModelCriteria
Fixed notice
Merge pull request #494 from marcj/patch-1

Fixed notice
Propel2-418 Saving and Resaving
-created test for triggering array to string conversion