Use initialisation lists for MythEvent constructors. Cppcheck warning.
Move MythSystemPrivate out of public interface header.
Add some needed headers
Remove compat.h & signal.h from mythsystem.h

We don't want to include unnecessary headers in mythsystem.h.
This may break on some of the other builds, I'll fix as needed.
Add missing header include
Coding standards fixes and initialisation improvements for MythUIGuideGrid. Fixes some cppcheck warnings
Initialise member variables in ATSCEvent. Strictly speaking this isn't
necessary as they are initialised immediately after creation, but all
static analysis tools complain about this and it's safer in the long
term

Refs #5106
Use initialisation list for RawDataList (Nuppeldecoder). Cppcheck performance warning
Use initialisation list for MythMusic's RipStatus class. Cppcheck performance warning
Remove redundant initialisation from MythUIGuideGrid, forgot to remove in 5748540
Merge remote-tracking branch 'upstream/master'