Now References can be disabled to meassure a compile time impact. Also the same examples are now provided in two subdirectories to be able to easily compare the pros and cons of every quantity construction technique.
We had some fun exploring the STD UDLs for potential collisions,
we have learnt our lesson and know how to proceed.
Now is high time to start behaving and obeying C++ rules.
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
