wasapi: Implement workaround for system timer coarse granularity caus…

…ing underruns by using timeBeginPeriod/timeEndPeriod APIs inside the Event and Poll thread handlers. Update next sleep time of the Poll rendering loop dynamically depending on time taken for processing/rendering of audio data into the available host buffer to avoid underruns and fit processing time into periodic polling time slots. Added support for time slots logging in Poll mode if PA_WASAPI_LOG_TIME_SLOTS is defined.