[pvr] EPG hookdata: Return UniqueBroadcastID

Returns epgUid known by client instead unset data.
correct codec names, MPEG is always written in upper-case
[cosmetic] add missing "l" in some comments
FIX: [linux] fix & optimize input device checking
linux: use CLOCK_MONOTONIC_RAW as this is not subject to NTP
[musicdb] drop filename CRC from the songview - it's not used for anything useful, and the filename is indexed anyway
[musicdb] drop setting of unused strKaraLyrFileCRC column in karaokedata table
[dbwrappers] drop unused ComputeCRC() function
[guilib] cleanup the navigation actions in controls to hold them in a map instead of 8 members.
[guilib] drop SetNavigation, SetTabNavigation from CGUIControl
[guilib] switch SetNavigateActions() to take an ActionMap instead of individual parameters
[videodb] move AnnounceUpdate|Remove to statics
[announces] add 'transaction' attribution to OnUpdate, OnRemove if scanning.
drop unneeded tracking of database updating, using the 'transaction' attribute of OnUpdate/OnRemove instead
[musicdb] NULL out entries in the song, karaokedata and album tables that are no longer used.
VDPAU: improve error handling
Merge pull request #4611 from jmarshallnz/gui_action_cleanup

Gui action cleanup
Merge pull request #4604 from jmarshallnz/drop_file_crc

Drop file crc from music database
[build] enable gtest configure by default.
Merge pull request #4635 from FernetMenta/linux

linux: use CLOCK_MONOTONIC_RAW as this is not subject to NTP