New features and bug removing

- added scrolling with mouse
- correct some bug
- added files  MIDIDriver_alsa.h and MIDIDriver_alsa.cpp (completely
untested)
- updated documentation
Separed horizontal and vertical tests

Two new test files: test_Fl_MIDIKeyboard_hor.cpp and
test_FL_MIDIKeyboard_vert.cpp for separate testing of horizontal and
vertical placement
Ported to RtMidi

Reweitten  the class MKB_MIDIDriver using the rtmidi library.
Now it should be possible to implement MIDI out for other OS than
Windows.
Deleted DOXYgen generated documentation
Big update

Changes include:
- Fl_MIDIKeyboard.cpp: fixed some bugs
-Fl_MIDIKeyboard.h MIDIDriver.h MainPage.dox Doxyfille: updated
documentation
- RtMidi.h edited to auto determine the OS (via the new file Config.h)
- test_Fl_MIDIKeyboard_hor.cpp test_Fl_MIDIKeyboard_vert.cpp rearranged
the GUI
One more bug fixing

Added a "redraw()" in function scroll_mode()
Deleted .exe and .a files