Added main.cpp

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
Added structure of tests for state class init

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
Added first hashing function for string

Signed-off-by: Ian bell <ian.h.bell@gmail.com>
Merge branch 'v5' of https://github.com/coolprop/coolprop into v5