small imprevements

[MCWertGaming]

Term::Terminal should have an option to call std::cout << Term::cursor_off(); in it's constructor and should re-enable the cursor in the destructor.

Also a small fix for terminals like the linux TTY:
Terminal::savescreen() should also do std::cout << Term::clear_screen_buffer() << std::flush;after saving the screen to avoid left over characters on terminals that do no support the save and restore ANSI codes. Also the restore function should do the same and move the cusrsor to 1,1 before restoring the screen to avoid lefover characters and black space (otherwise the prompt would be on the line where the cursor was).