[mythtv] MythTV UTC branch merge

[danielk]

I've just merged the UTC branch to master. I've been running this
branch locally so I don't expect any huge problems. However this
is a fairly large change touching all parts of MythTV so I expect
there will be some problems I haven't encountered and fixed already.

This changes the internal representation of time in the database
and in the code from local time to universal coordinated time.
To the end user this means there will no longer be problems when
daylight savings time starts or ends and there won't be any problems
with connecting two machines in slightly different timezones.
i.e. "Americas/New_York" and "New York" when the machines have
two different operating systems.

For developers this means using the functions in mythdate.h
to get the current QDateTime and to format a date for output.
The QDateTime returned from Qt classes such as QFileInfo
are also in local time which means that if you plan to store
the date for future reference you should call QDateTime::toUTC()
so that it will be stored in UTC. However, if you are just
comparing it to a QDateTime in UTC Qt is smart enough to
compare them in the same timezone.

-- Daniel