[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