dvdplayer: ff/rw/seek was broken for inputs implementing IDisplayTime

This affected PVR with file based inputs and BluRay.
CGUIMediaWindow: fix invalid filter-path when toggling watched mode which leads to not grouping into movie sets
dvdplayer: another fix for seeking/fw/rw in PVR
[pvr] fix channel import for mysql backends. closes #13810
fixed - don't try to go to the previous window when stopping playback on exit. closes #13884
[pvr] fixed canceling the active timer on a channel in certain situations
moved nyxboard power and user button from peripheral config to keyboard.xml
reset initial visible state to visible if it has been set to delayed during a previous window session. fixes #13923
revert part of 60b0ee01a47a134a002594ab746b2e52efb0d2b7 that somehow snuck in
view control in login window was cleared on deinit rather than on unload. fixes #13813.
album art for individual songs in file mode weren't loading correctly - fixes #13906
always add the repository to the add-ons database even if it returns no add-ons. fixes constant (every 10 minutes) hitting of add-on repos that have no add-ons
Correct handling of multimedia key presses
[cec] don't send incorrect pause/resume to slideshow when the source is (de)activated and don't resume playback when the source is activated and we didn't pause it when the source was deactivated
[cec] don't update the device type in settings with the value that was returned from libCEC
Fix for timestamp problems commonly seen with avi files.
write id3v2 tags when ripping cds to mp3
[cddb] use uint32_t for the disc id rather than unsigned long and other permutations - it has to be 32 bits. fixes #13933.
fix horizontal alignment of outlined text. fixes #13909
[jpegio] use chunked reading in case the filesize isn't available on Open()