Remove DemoPlugins

Not built, not needed, so remove them. Even as examples they fail.
MovieSelection: Fix some whitespaxes
MovieSelection: Add option to hide known extensions

And remove some more white spaces
MovieSelection: Better description an simpler coding
UsageConfig: Latvian should be lav instead of lat

Thanks Artis

See: http://openpli.org/forums/topic/21339-automatic-language-subtitle-settings-improvements/page__st__40
configure.ac: simplify vu+ boxtype detection
MovieList: Add pictures to the known extensions

And do it slightly different - thanks DeBeek
MovieSelection: Remove delayTimer use callLater instead

As callLater does in fact the same
MovieSelection: Remove extension code/data duplication and speed it up

Put the "known extension types" lists in one spot for easy maintenance.

Doing "a in (very,big,tuple)" will sequentially scan all elements of
the tuple. This is much slower than a set or frozenset which uses a
hash lookup.
InfoBarGenerics: Some tiny timeshift related fixes

Fixed when going to MovieSelection and directly exit that timeshift
could be started, but not played anymore.
Remove PVRState when zapping/selecting different service that also
stops the timeshift.

I still discover some strange things in case the timeshift buffer
does not have much time yet (< 1 min) and we step skip back. This
is not fixed (yet)
InfoBarGenerics: Some cosmetic cleanups regards Timeshift

Use True and False instead of 0, 1 and False mixed up together
for timeshift_enabled and remove not used declared timeshift_state
InfoBarGenerics: Ensure timeshift is stopped when zap
InfoBarGenerics: set seekstate to play when not seekable in timeshift

Thanks ims and also ensure to stop when zap was not a good idea...
settings and net moved from movielist menu under color buttons
typo in NationalOptionSubsets for czech
opkg: Handle new packaging output

Just parse the OPKG files directly, that's much easier than parsing
opkg's rendering. The v4 packaging has some nasty habits:
- multiline descriptions
- repeating package name and version in the description
- wrapping lines in odd places (adds extra spaces to versions)
This works around those.
Fix opkg.py to work with older opkg versions

Prevent "duplicate" packages.
MovieSelection: Keep settings and network items in list

A skin change is needed to "see" the colored buttons, so people with
other skins will wonder where they went.
Fix Button and Label classes to mimick Source to support generic templates in skins.
Disable overcommit for non-workstations.

This allows the STB to reliably report how much memory (including swap)
is available at all times, and consequently means that the OOM-killer
is never invoked (and thus no unexpected crashes due to that).