This patch introduces MyMoneyStorageMgr class to avoid needless duplication of virtual methods in IMyMoneyStorage and IMyMoneySerialize and juggling between those two interfaces.
It's a cornerstone for getting rid of MyMoneyObjectContainer as universal cache.
Its code consists in big part from well proven MyMoneySeqAccessMgr and lends its capabilities to MyMoneyDatabaseMgr. Therefore databases now work just like xml file, i.e. read to cache, make all operations on cache and save to the file at the end of program. This brings us speed and unified code path.
MyMoneyDatabaseMgr looked like duplicate code and had a little bit different logic in two places, which shouldn't happen. That's why tests had to be heavily modified and now are probably duplicate of MyMoneySeqAccessMgr test.
If a database should be connected in real-time to KMyMoney then it's not possible at the moment and for sure shouldn't be solved as it was solved before.