Added create method to BaseModel
Made to_dict and to_json converter recursive
Attached BaseQuery class to Database class
Removed proxies session methods from Database
Used DeferredReflection Mixin to reflect tables from database
Build all database relationship
Merge branch 'master' of git+ssh://scm.gforge.inria.fr//gitroot/oar/python-oar-lib

Conflicts:
	lib/oar/database.py