Refactoring Trade class, now extending Entity.
Fixing legacy code that reference Trade class.
Deprecating Operation class.
Refactoring: changing Long to long to simplify the development, to get
better performance e get less memory usage.

TEST
- Unit test of Trade class
Merge branch 'master' of
https://github.com/lgsanjos/RendimentosFinanceirosApp.git

Conflicts:
	appTest/src/br/com/itibansistemas/rendimentos/stock/StockRepositoryTest.java
	appTest/src/br/com/itibansistemas/rendimentos/stock/StockTest.java