* IDEMPIERE-4287 Cache API not thread safe and inconsistent with Context
add support to make PO immutable
* IDEMPIERE-4287 Cache API not thread safe and inconsistent with Context
- added thread safe Immutable and Copy cache implementation for PO.
- migrate most of PO cache to immutable and copy cache.
- added pos sales order test.
* IDEMPIERE-4287 Cache API not thread safe and inconsistent with Context
- add test case for initial client setup and bank statement
- fix error for image editor, location editor, locator editor, initial
client setup, complete bank statement and migrate storage provider.
* IDEMPIERE-4287 Cache API not thread safe and inconsistent with Context
- added ImmutablePOSupport interface. Model class implement this
interface for immutable PO support.
- remove usage of cache for transaction table (rfq, invoice, inventory).
- add getCopy method to some model class to support getting an
updateable copy of PO from the otherwise immutable PO cache.
- the added getCopy method is use to return updateable PO for indirect
PO reference, for e.g MColumn.getAD_Table() and MOrderLine.getProduct.