Minor patch

• Some C++17 type_traits were used by mistake instead of the C++14 one.

First release

First complete user experience. Among others, the following basic functions have been implemented:

• SI units
• Astronomical units
• CGS units
• Imperial units
• Computer Science units
• temperatures
• affine types
• unit conversions
• unit math
• conversions between builtin types and the unit 1.
• user defined dimensions, units and constants/symbols
• named dimensions
• arbitrary prefix conversions
• unit compatibility helper
• examples
• unit tests