REQS-147 - Futures convexity adjustment calculation

Add in basic data structures to support convexity
adjustment during curve construction
REQS-147 - Futures convexity adjustment calculation

Initial part of documentation
REQS-147 - Futures convexity adjustment calculation

Enhance basic data structures to support convexity
adjustment during curve construction
REQS-147 - Futures convexity adjustment calculation

Add in basic data structures to support convexity
adjustment during curve construction
REQS-147 - Futures convexity adjustment calculation

Reformatting
REQS-147 - Futures convexity adjustment calculation

Add extra test
Merge pull request #192 from OpenGamma/topic/REQS-147

Topic/reqs 147