[PLAT-6777] Fixed coupon stub in annuity builders

Also includes [REQS-648] Added tests for stub handling
[PLAT-6849] Test stub periods of swap in annuity builders
[PLAT-6849] Added tests, simplified annuity builders
Merge branch 'develop' into topic/REQS-648

Conflicts:
	projects/OG-Analytics/src/test/java/com/opengamma/analytics/financial/instrument/annuity/FixedAnnuityDefinitionBuilderTest.java
	projects/OG-Analytics/src/test/java/com/opengamma/analytics/financial/instrument/annuity/FloatingAnnuityDefinitionBuilderTest.java
[REQS-648] New par rate calculator added
[REQS-648] Code tidy-up
[REQS-648] Resolved type safety warning
[REQS-648] Add more tests, argument checkers.

Also support for receiver's swap in generator, note in annuity definition
Merge pull request #288 from OpenGamma/topic/REQS-648

Topic/reqs 648