Fix packet/frame counter for pulseaudio plugin

Reset the counters when the recording is stopped.
Fix requested latency for pulseaudio plugin

When the PA_STREAM_ADJUST_LATENCY flag is passed, pulse will interpret
the fragsize attribute as a literal targeted latency.
Remove pa timestamps option from pulseaudio plugin

Due to desync issues with the pa timestamps, os ones are
now the only option.
Merge pull request #92 from fryshorts/pulse-input

A few smaller fixes for the pulseaudio plugin