Dimensionless quantities are now represented by quantity types rather
than by plain representation types. Only dimensionless quantities with
`unitless` unit are implicitly convertible from representation types.
`units::exp()` now is a function doing std::exp() on a representation
type (previous `units::exp` class template was renamed to
`units::exponent`).
BREAKING_CHANGE: gcc-9.3 support removed
BREAKING_CHANGE: `exp` and `Exp` renamed to `exponent` and `Exponent`
Resolves#27Resolves#42
Added dim_angle, Angle concept etc.
Not really for merging, but fun to play with.(The main problem is that it doesnt conform to SI)
See https://github.com/mpusz/units/issues/99
Could try adding degrees etc in same way as non-si units
Add si::density quantity header .
Add si::resistance quantity header.
Update si::capacitance header with mF, uF, nF, pF.
Update si::voltage header with mV, uV, nV,pV
Third party example : add capacitor time curve example
Add incoherent length units, TODO move them out from si header.
Third party examples : add clcpp_response showing effectivenes of typed units for physical quantity library
Third party examples : add conversion factor example
Add third party examples to cmake
Third party examples : box example : Add air_density constant for clarity remove explicit this-> and tidy up.
Third party examples : in clcpp response example, change base unit from km to m for single type or all units example.
Third party examples : conversion_factor , add inline constexpr to units_str function.
Third party examples : box_example, change quantity::unit syntax to quantity::unit<> to allow generic(default double) value_type.
examples : remove examples from third party to main examples directory. Update cmake.
physical/si/resistance.hpp : remove underscores from kiloohm etc, UDL collision with 'R' so prefix with underscore
