Generic module to compute the stock quantity available to promise using several implementations.
stock_available_immediatly is changed to become the first optional implementation.
Cherry pick of commit 0b060f619f from the v7 branch
[IMP] stock_available* uses new API
[IMP] READMEs and TODOs
Cherry-picked from v7 at 8add4bea7e
Conflicts:
__unported__/stock_available_mrp/__openerp__.py
stock_available/__openerp__.py
stock_available_immediately/__openerp__.py