Changed the -q option to now specific the minimum buffer size

rather than maximum.  Maximum queue size is now twice the minimum size.

As per "Re: [openob-users] clicks on audio" - setting the maximum doesn't make much sense as the queue will allow reads before any samples are in the queue (i.e. the min-size-time param is 0 by default).

https://github.com/JamesHarrison/openob/issues/19