[MediaPortal] Put CDateTime into MPTV namespace.
Fixes a crash on Linux where the addon accidentally accessed member functions from XMBC's version of CDateTime.
[MediaPortal] Add missing GUIDialogSettings.cpp to Makefile
Fixes a crash when creating a new timer
[MediaPortal] Detect and report permission denied errors on Live/Recording access
[MediaPortal] Properly close an ongoing timeshift when opening fails.