[untracked] added stat output for requested frames number
[untracked] implemented headless mode for tests

- implemented non-ncurses headless console mode; all the parameters can
be specified by configuration file;
- added signal handler to demo app; app shuts down gracefully when
receives SIGUSR1;
[untracked] removed test_app folder
[untracked] removed .gitmodules
ref #1068 [updated README and INSTALL files]