reduce buffer_time and period_time

max_buffer_size can be huge. I have seen value over 1M frames!
That means period_sime of 500000 frames and period_time of about
11 seconds at 48KHz. On top of putting incredible latency in the capture,
this is making huge audio packets.

in the same occasion, I have fixed alsa_capture that I broke with my refactoring
because of a race condition.

oh and yes, alsa_capture ends up using glc ALSA overloaded functions as I though it was.
Will fix that next.