add compilation.h
add problem.h
add solution.h, testing.h and user_interface.h (all not ready)
add functions to problem.h
may be finally realisation of testing.h
change some functions and structs in compilation.h and solution.h
Pull request fix
Merge pull request #1 from cmc-freedom/headers

Headers (bad thing)
Merge remote-tracking branch 'origin/master' into wide-system