Generate Count-In Beats

I've added the following items to create a count-in screen ability:

command line options beats, count-in, and tempo.

generateBeats to create screen

generateBeatsSilence to create silence

I've modified the following

the ffmpeg cat command to combine videos; I simply made this look for title, beats, and notes. It will probably fail if you leave one out. This needs to be improved.

generateSilence has become generateTitleSilence to differentiate from generateBeatSilence

and probably another thing or two. But I guess this is what git is for (to keep track of my changes). First time doing this sort of thing.