* rename "latency correction" to "write index correction"

* rename "latency correction" to "write index correction"
* add read index invalidation code
* rename "ipol_event" stuff to "auto_timing_update"
* remove buffer_usec field from pa_timing_info, since it can be easily calculated from write_index and read_index anyway
* add read_index_corrupt field to "pa_timing_info", similar to the already existing write_index_corrupt field
* restart automatic timing update event every time a query is issued, not just when the last event elapsed
* proper invalidation code for pa_stream_flush()
* do tarsnport/sink/source latency correction for playback time only when device is not corked

git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@686 fefdeb5f-60dc-0310-8127-8f9354f1896f