[xcode] add iOS Target to main Xcode project

* iOS Target added
* add build phases from iOS project
[xcode] add sources for iOS build & configure targets

* factor out most of the configuration into xcconfig files
  this should help in tracking down changes in the build configs,
  make diffs easier and such.
* provide a xcconfig cascade for the project level (Common -> Debug/Release)
  as well as on the target level (App -> App-OSX/App-iOS)
[xcode] remove UnrarXLib{.sln,.vcproj} from xcodeproject
[iOS] fix linking with UnrarXLib

move -DSILENT back to project and only define it
on the UnrarX cpps. Otherwise a somewhat strange
#define Log(…) kicks in from UnrarXLib/log.hpp which
breaks our CLog:Log(…) statements
[xcode] externalize Codesigning into a shell 'command'

* check gen_entitlements and log a proper error
* use external command for easier diffing / editing
[ios] remove unused XBMC-iOS xcodeproject
[jenkins] adjust build script to point to iOS Target
[iOS] add support scripts to Xcodeproject
[iOS] extract CopyRootFiles from Xcode
[iOS] match more build settings to old xcodeproject
[xcode] - don't codesign from within xcode
[xcode] - fix framework include path (take it from sdkroot)
[xcode] - add atv2 target to merged xcode project
[xcode] - move all buildsteps into shell scripts
[jenkins] - change jenkins buildsteps for atv2 to use the merged xcode project
[xcode] - fix TARGET_DARWIN definitions and add xcconfig for the new ATV2 target
[xcode] - fixed missing shell entry for genoutputdirlink.command
[xcode] - added the new support shell scripts to xcode project
[doc] - updated READM.ios for using the merged xcode project
[xcode] - removed obsolete xcode project for ATV2