Disable channel icon scan when icon path is empty

XBMC checks the icon path and terminates the scan early if no path is set. This commit causes the setting to respect that.
PlayList::LoadData: fix loading data
Seems that it was never work on Win32
Also unify for platforms, remove CStdString
fix compile warning (assignment inside if)
fix HasExtension didn't necessarily terminate correctly
[osx] - fix windowed/fullscreen transitions with multi screen setups
[osx/mavericks] - ugly hacked fix for the mouse bug (mouse wasn't able to move over the full screen) - intermediated isolated hacked solution until new windowing is ready
[xcode] - remove stale references to ios6.1 sdk
Merge pull request #3516 from Memphiz/osxmultiscreen

[osx] - fix windowed/fullscreen transitions with multi screen setups
Merge pull request #3392 from garbear/pvrmenu.searchicons

Disable channel icon scan when icon path is empty
Merge pull request #3506 from jmarshallnz/compile_warnings

Compile warnings
Merge pull request #3517 from Memphiz/mousemavericks

[osx/mavericks] - ugly hacked fix for the mouse bug (mouse wasn't able t...
Merge pull request #3510 from Karlson2k/PlayList_fix_01

Fix loading data in CPlayList::LoadData
fix to handle 'None' passed as a parameter from python.
jsonrpc: fix "limits" for PVR.GetChannels