Move test market data builders to trait
Merge pull request #17 from thoozaho/master

PositionPivotReport
Previous merge omitted file
Merge pull request #18 from thoozaho/master

Previous merge omitted file
NBPs swaps and futures

Added valuation and position code for NBP which is
 in THM/DAY
Merge pull request #19 from og3b/master

NBPs swaps and futures
Added spot fx and forward fx

Spot date calculations look mostly sensible. FXPair is an attempt to
 stay sane about which way up the fx pair is. Same with
 UOM.toString now returning (for example) USDGBP for the uom GBP/USD.

Added FXForward instrument
Merge pull request #20 from og3b/master

Added spot fx and forward fx
Move test market data builders to trait
Minor refactorings of hedging

1. Creation of a HedgingInstrument trait that has a volume
2. Replaced SwapHedgeInfo and FuturesHedgeInfo with plain HedgeInfo
3. To avoid confusion with FuturesMarket, the terms 'riskMarket' and
   'riskPeriod' are used in hedging (and position reporting).