[PLT-430] Added coupon ibor with fx reset: definition and derivative
[PLT-430] Implemented pv, sensitivity, fx exposure calculators
[PLT-430] Test for CouponIborFxReset and its definition class
[PLT-430] Tests for pv, sensitivity, currency exposure calculators

Reverted the change for coupon ibor spread calculator
[PLT-430] Added swap example
[PLT-430] Extended toDerivative test, added javadoc for individual tests

Also changed variable names for ibor index fixing
[PLT-430] Added a missing javadoc
[PLT-430] Added tests for toDerivative without time series
Merge pull request #216 from OpenGamma/topic/PLT-430

Topic/plt 430