output image_optim version when running in verbose mode
ImageOptim.full_version => "image_optim vA.B.C" + usage
Merge branch 'verbose-output-version'
test ignoring broken images
test ignoring broken images also at path
don't create temp file if format of image data can't be detected
ImageMeta for detecting image format
ImageMeta: rescue exceptions and warn, partially #43
Merge branch 'broken-images'