[rbp/omxplayer] Fixes for trickplay

In #2955 we lied in GetTime when in trickplay modes to avoid jittery updates in elapsed time.
This was wrong when GetClock() didn't match the media time (e.g. when playback was started from a bookmark).

The jitter is caused by the DISPLAYTIME messages that don't really work on omxplayer.
Instead bypass the DISPLAYTIME messages and set the time explicity in OMXPlayer (using media time where appropriate).

Also in trickplay, do the seek/flush step more to fix an issue when going from normal to rewind after EOS

Also don't honour the "accurate" seek flag, as it results in corrupt frames being displayed
settings: split requirement conditions from <visible> conditions into new <requirement> tag
[win32] update VS project files
settings: implement new "visible" dependency for dynamically showing/hiding settings
remove check if running from DVD. this is XBOX legacy which isn't used anymore
Merge pull request #3061 from MartijnKaijser/xbox_legacy_dvd

remove check if running from DVD
added: generate and install cmake helpers for addons
Merge pull request #2981 from cptspiff/cmake-rules

added: generate and install cmake helpers for addons
[osx/ios/atv2] - sync xcode project
Merge pull request #3038 from popcornmix/improve_ffrew

[rbp/omxplayer] Fixes for trickplay
[cosmetics] - get rid of some checks for _WIN32 and replace them with proper TARGET_WINDOWS checks
[rbp/omxplayer] Fix build error in types for max

It seems there is a compile error when STDINT_H_AVAILABLE is not defined.
See: http://raspbmc.apt-get.eu/downloads/bin/xbmc/nightlies/xbmc-rbp-20130710.log
Merge pull request #3067 from popcornmix/fix_compile_max

[rbp/omxplayer] Fix build error in types for max
[rbp/omxplayer] Fix uninitialised variable that can lose audio packet

The uninitialised variable meant the first run through Decode goes through the non-passthrough path (when passthrough)
and so doesn't get correctly submitted and is discarded
[rbp] Fix type of transform parameter to match latest firmware
Merge pull request #3071 from popcornmix/uninit_audio

[rbp/omxplayer] Fix uninitialised variable that can lose audio packet
music: fix crash when calling CTagLoaderTagLib::Load() through IMusicInfoTagLoader::Load() (introduced by d0a5a97e0c6c7831db382dfdc3e8650ff500acb9)

The class definition of CTagLoaderTagLib was completely screwed up. It is used
as if it was derived from IMusicInfoTagLoader but it actually wasn't.
Furthermore the signature of the CTagLoaderTagLib::Load() method was not
completely identical to the pure virtual method definition in
IMusicInfoTagLoader (std::string instead of CStdString) so it's a miracle this
didn't blow into our faces earlier.
Merge pull request #3076 from Montellese/tagloader_fix

music: fix crash when calling CTagLoaderTagLib::Load() through IMusicInfoTagLoader::Load()
Merge pull request #3073 from popcornmix/transform_type

[rbp] Fix type of transform parameter to match latest firmware
[rbp] Switch from libshairport to libshairplay for airplay