fixed bugs, including “No thumbnails are shown on iOS7” “ghost thumbnail”.
optimize the location feature
optimize the sort algorithm
fixed bug for sort of asset group list
repair a big memory leak
optimize the interface for class
optimize the  subviews memory mgr
1、support the picker preload
2、picker instance support user is denied flag
1、support the picker preload
2、picker instance support user is denied flag
1、support the picker preload
2、picker instance support user is denied flag
1、support the picker preload
2、picker instance support user is denied flag
1、support the picker preload
2、picker instance support user is denied flag
opitimize init method
change check mark to iOS 7 style
add .gitignore
fixed some memory leak
Merge branch 'master' of github.com:SpringOx/AGImagePickerController

Conflicts:
	AGImagePickerController Demo.xcodeproj/project.pbxproj
	AGImagePickerController Demo/AGViewController.m
	AGImagePickerController/AGIPCAlbumsController.h
	AGImagePickerController/AGIPCAssetsController.h
	AGImagePickerController/AGIPCAssetsController.m
	AGImagePickerController/AGIPCGridCell.h
	AGImagePickerController/AGIPCGridCell.m
	AGImagePickerController/AGIPCGridItem.h
	AGImagePickerController/AGImagePickerController.m
Merge branch 'master' of github.com:Xummer/AGImagePickerController

Conflicts:
	AGImagePickerController/AGIPCGridCell.m