Optimize png images with optipng -o7
Merge pull request #309 from Nikerabbit/opti

Optimize png images with optipng -o7
Merge remote-tracking branch 'upstream/master'
Validate inputmethod ids while constructing menu

See https://bugzilla.wikimedia.org/show_bug.cgi?id=55701
Merge remote-tracking branch 'upstream/master'