For Resample.* and QualityPrefs.cpp, this commit has my restructuring for distinguishing constant-rate vs variable-rate resamplers more generally. I think it's complete and ready for const-rate, but I have more review and testing to do for the var-rate cases.
Variable-rate resampling is not implemented here, so Time Tracks are still broken, but this is a milestone in getting to a more general and correct structure.
Also I think this fixes AboutDialog issues Steve noticed.
* Fix P2 bug described by Bill Wharrie in "Problem dragging clips between tracks with different sample rates" thread on audacity-quality. Made sure the clips get resampled to the destination WaveTrack rate, and marked changed.
* Comment out unused override of WaveTrack::MoveClipToTrack().
* Added an ANSWER-ME about what appears to be a useless declaration and assignment.
In WaveClip.cpp, remove wxASSERT that Michael was trying to convince me to do yesterday. In debugging this, found a case when it's not a bad call. Thanks, Michael! :-)
In TrackPanel.cpp, removed some cruft.
* Fix memory leaks.
* Add comments about initializations and checking for successful results.
* Add checks for NULL deref.
* Consistency in "TODO" vs "TO-DO" comments!
Correct Sequence::ConvertToSampleFormat() errors resulting in wrong block file sizes, per offline discussions with Martyn and James.
In WaveClip::ConvertToSampleFormat(), distinguish between failure and no change.
Changed deprecated calls to wxArray::Count() to GetCount(),
In Sequence::Blockify(), no reason to call Alloc() if we know we have no samples, so rearranged that code.
Changes per Martyn's suggestion (http://bugzilla.audacityteam.org/show_bug.cgi?id=451#c24), i.e., deal with sample format mismatch in WaveClip::Paste() and Sequence::Paste().
Also add error checking for bad s parameter values passed to Sequence::Paste().
