use method_defined + simpler regexp in method_missing
optimize_image_data: writes provided data to temp file, optimises and reads out if optimisation was successfull
move conversion to ImagePaths from run_method_for
optimize_images_data: optimize_image_data for multiple image datas
railtie + readme
Merge branch 'master' into rails

Conflicts:
	image_optim.gemspec
ImageOptim#to_image_path preserving instance if it is already ImagePath (fixes GC.start unlinking file created by temp_path if it was rewrapped into new instance)
Merge branch 'config' into rails

Conflicts:
	README.markdown
Merge branch 'rails'