Alternative (additional) playback keyboard controls

[W3bbo]

For use with remotes with limited buttons, it would be useful to be able to use the d-pad and OK button to control recordings and live TV e.g.

Enter - Pause / Play
Cursor Right - Skip forwards
Cursor Left - Skip back

These could be used in addition to the existing shortcuts and I do not believe these would conflict with any existing bindings.

In addition, this would keep a consistent behavior when using NextPVR alongside other platforms such as Plex / XBMC.

[W3bbo]

Thanks Sub for adding the left and right shortcuts in 3.7.7:

- added playback keyboard controls that don't require Ctrl key for common activities. ie, spacebar to toggle pause, F to fastforward, R to rewind, right-arrow to skip forward, left-arrow to skip back. Will look to extend this to other keys if users recommend further actions they'd like to access with single key.

One additional suggestion I would add is to also allow Enter to be used as a play / pause button which would then allow all common playback functions (skip forward and back, play and pause) to be operated from the D-pad on a remote.

Thanks as always for a great application!