Add invoice type
Update KeyGenerator
Update invoice handler tests
Merge branch 'platypus-fix' of github.com:premium-minds/billy into platypus-fix

Conflicts:
	billy-platypus/src/test/java/com/premiumminds/billy/portugal/test/services/dao/TestDAOPTInvoice.java
	billy-platypus/src/test/java/com/premiumminds/billy/portugal/test/util/PTInvoiceTestUtil.java