implement brand account using mapped super class of accountKeys

git-svn-id: https://brain-invoice.googlecode.com/svn/trunk@7 e6ef879c-6efb-f92a-4ca0-37fcd3c99b0e
add implementation of hashcodebuilder,equalsbuilder and tostringbuilder
using commons-lang library.
TODO: implement all this on every entity classes
Merge https://github.com/yudhik/brain-invoice

Conflicts:
	brain-invoice-model/src/main/java/com/brainmaster/apps/invoicing/model/id/AccountKeys.java
	brain-invoice-model/src/main/java/com/brainmaster/apps/invoicing/model/id/BrandAccountKeys.java