Change default Xinerama aspect ratio to widescreen

and re-order the list in setup.

Note that anyone using Xinerama should still specify a proper aspect
ratio using the setting:

Monitor aspect ratio
The aspect ratio of a Xinerama display cannot be queried from the
display, so it must be specified.

in frontend Appearance settings, but since many users seem to miss this
setting after enabling Xinerama, this change updates the default to a
value that's more likely to be right, today.
MythMusic: fix Coverity ID 1026182 Use after free
MythMusic: fix Coverity ID 1026178 Uninitialized pointer field
MythMusicVolumeDialog: fix Coverity ID 1026179 Uninitialized pointer field
MythCommon: Move some code to where it should be

Fixes Coverity ID 1026181 Structurally dead code (genuine bug).
DecoderIOFactoryShoutCast: fix Coverity ID 1026180 Uninitialized scalar field
StreamView: fix Coverity ID 1026167, 1026168 Dereference null return value
StreamView: fix Coverity ID 1026165 Dereference after null check
Give 'find' a path so it behaves on FreeBSD
Reduce the tightness of AddMSecsWorks() bounds.

The time elapsed is in the range 30-34 on a Gentoo system.

As long as the elapsed time is between 25 and 51 ms the addMSecs call did work,
it may just take longer to get our timeslice back on some systems than others.
Remove unnecessary include.
Properly link with zmq stuff in tests.

When running the tests we were dynamically linking with the
installed versions of these libraries rather than the just
compiled versions as we should be.

Thanks go to Raymond Wagner for identifying the problem.
MythMusic: fix Coverity ID 1026166 Improper use of negative value

In Ripper::toggleTrackActive(MythUIButtonListItem *): Negative value can be
returned from function is not being checked before being used improperly

The only way this could be a problem is if item doesn't exist which is very
unlikely.
MythMusic: fix Coverity ID  1026169 Resource leak

In EditMetadataCommon::scanForImages() image was not being deleted.
MythMusic: fix Coverity ID  1026175,1026176,1026177 Uninitialized variables
AvfDecoder: fix several Coverity detected errors

* 1026172 Uninitialized scalar variable (fill).
* 1026173 Uninitialized scalar variable (total).
* 1026164 Division or modulo by zero - this looks like a false positive
          because m_inited will be false if m_sampleFmt is FORMAT_NONE
          which is the only way the division by 0 can happen.
MythMusic: fix Coverity ID 1026174 initialise several variables in ThumbFinder
mytharchivehelper: fix Coverity ID 1026163 remove some logically dead code
Add new MythSystem. Rename old MythSystem to MythSystemLegacy.

This commit creates a new simplifed and less ambiguous MythSystem API.
The old MythSystem has been renamed MythSystemLegacy and provides
the current implementation for the new MythSystem.

The next steps are:
   Complete unit tests for new MythSystem,
     fixing bugs as they are found & enhancing MythSystemLegacy as necessary.
   Port code over to the new MythSystem interface.
   Get a windows buildbot running.
   Eliminate MythSystemLegacy unit tests.
   Refactor MythSystemLegacy to support only the new interface.
   Eliminate any unneccesary abstractions.
Port existing MythSystem tests to the new interface.