New field ImageUploadField replaced old FileUploadField
ImageUploadField includes options for cropping, resizing and multiple
thumbnails. It automaticly created hidden form fields for field.
Currently image cropping working for multiple image uploads on same
form.

Fields and widgets belongs to image uploading moved under
admin/components/image_upload also whole image uploading functionality
will be there.
Uploads folder wont be tracked anymore
Image upload process refactored into component
Refactored - image upload handler function
The function decorates and wrap the on_ methods
Merge branch 'feature/image-upload-refactoring' into develop

Conflicts:
	.gitignore