Restore compatibility with GraphicsMagick.
Commit 302aaa3 added the -quiet option on identify commands. This broke compatibility with GraphicsMagick as there is no such option for their implementation identify. It may make more sense to put in the mini_gmagick file but here's the quick fix.
Support loading images from [Tempfiles].
removes 'string' from MOGRIFY_COMMANDS
… 2.1 to 2.0 dependency