Add cubic volumes and oil barrels

Added cubic metres, cubic feet, cubic inches and oil barrels to volume

v1.0.12

Added millisecond, nanoseconds, microseconds to README.md

NuGet release version

This is the first (non-prerelease) release since rewriting of the code to use the code generator

Additional converts and precision fixes

Added FuelEconomy & DataStorage converters. Also fixed some precision issues in the definitions file.

v1.0.0.0-alpha

C# idiomatic release in sync with FSharp.Units v1.0.0.0