bump beta2
 added apply_concurrency_check
fixes #4 (thanks FrankBie)
new signal based wrapping
new arg manual
removed relative imports
bump 0.4b3
- some refactoring
- fixed mysql
-added travis test for multiple db engine
fixed travis (?)
fixed travis (?)
another test with travis
another test with travis multidb
another issue with travis
another test with travis
another test with travis
multiple database travis configuration
fixed travis/postgres cfg
just code clean and beautify
Merge remote-tracking branch 'upstream/master'

resolving Conflicts:
	concurrency/core.py
	concurrency/fields.py
	concurrency/tests/__init__.py
	concurrency/tests/all.py
	concurrency/tests/models.py
	concurrency/utils.py