Add command-line tool wich will generate C++ file with parser

[metthal]

Pog is able to generate parser during the runtime but it takes some time to actually create the parser itself. In the same way as bison and other parser generators, we should add CLI tool which generates C++ files with the parser itself. It would give an option to people which do not want to generate parser during the runtime.

Even though pog was created as a mean to replace bison because of problems of integrating it into CMake build system, we can still use the generated C++ file without actually running the pog each build.