Disable cross-fading between tracks with different sample rates

Cross-fading between tracks with differing sample rates (eg 44.1kHz
ripped from CD and 48kHz high quality downloads) appears to cause an
alarming burst of white noise at full volume during the cross-fade
period. This is the case for my Squeezebox Touch when using the
analogue outputs, at least.

This modification is an extension of the method used for 'smart'
cross-fade and temporarily disables cross-fading when transitioning
between tracks with different sample rates.

I believe this might fix
bug#1884 (http://bugs.slimdevices.com/show_bug.cgi?id=1884) -- a
golden oldie that is more than seven years old.
Don't return undef, as most callers are expecting some kind of ID.
Revert the Perl 5.10/Linux x86 build to Audio::Scan 0.94. There's a
problem with the latest 0.95
Add SQL schema changes for library support in MySQL. Thanks nrosier!
Revert the order in which we try to load the Audio::Scan binary module
versions. Some older Perl versions (5.8?) seem to have a problem trying
more than once or twice. Those systems most likely will never see more
recent Audio::Scan versions. Let's therefore try the oldest version
first.
Don't put commented out items inside the qw() list. Some perl versions
don't like this.
Bug 5108 - Track artist roles become artist roles when COMPILATION=0

Treat the undefined compilation flag the same as the explicit
compilation=0 case.
Add Perl 5.18 modules for OSX 10.10/Yosemite
Changelog update
Enhanced Substitution of strings

Enhanced Substitution of strings for variable capabilities to enable
better 3rd party transcoding
Add Perl 5.18 modules for OSX 10.10/Yosemite
Add PurePerl 5.18 modules for OSX 10.10/Yosemite to 7.7
Merge branch 'public/7.7' into public/7.8
Merge branch 'public/7.8' into public/7.9

Change-Id: Ie44f0e4d09a8fff96ed77801d4b3dd9619ade2ab
Changelog update
Merge branch 'public/7.7' into public/7.8
Merge branch 'public/7.8' into public/7.9
Bug 18105 - Scanner crashes on Synology and other systems.

Updated Audio::Scan module for i386/Perl 5.10.
Update Windows build to Audio::Scan 0.95

Change-Id: Ide9ad3e13cc132cf82ba1f4a4af6f79ee7a44938
Enhancements for virtual library support

- unregisterLibrary() - let's you remove a library
- rebuild() - re-build an existing library without running a full scan
- priority param allows developers to define the order in which
libraries should be built