Currently only sin, cos, tan, ln, sqrt, e, and pi, are recognised; although adding functions and constants is easy
+-*/^ are recognized as operations
CMDtool.cpp is a quick and dirty command line interface whose primary purpose is testing
compiled with Mingw64 on Windows 10
->may be unstable if nan or inf are unsupported
tested with fructose: http://www.andrewpetermarlow.co.uk/software/fructose.html
std::unique_ptr and its ilk is suspiciously absent for no apparent reason