Implemented full text search functions modes
Added new test cases for new search functions
Documented new changes for search functions
Separated FullTextModes into a separate module
Changed init mode to DEFAULT instead of None
Changed documentation and added new test cases
update test
Merge remote-tracking branch 'alejom99/master' into dev

Conflicts:
	sqlalchemy_fulltext/__init__.py
	test_sqlalchemy_fulltext.py
fix ut wrong count