Add loop count option

[mwoehlke]

This adds the ability to specify a "loop count". Because the library appears to expose looping as a "once set, never cleared" flag, the only way I could figure out to count loops was to take the number of samples until the "has looped" flag becomes set as the loop length. Accordingly, using both -l and -s will probably not work "correctly". However, this is much better than nothing.

See also #8.

[ildar]

Just found this one. Looks nice, I'll try to test it.

[ildar]

works fine for me.