Update vendor prefixes for transition property

Since we let Autoprefixer handler prefixes in core we have to add the non-prefixed version too. With our browser settings -moz prefixed version isn't needed, so we can remove it.
Merge pull request #19 from ocean90/patch-1

Update vendor prefixes for transition property
Updating to latest dashicons files. Adds new widget icons.

Props @marestad for the new icons and @empireoflight for recompiling
the font.
Merge branch 'master' into gh-pages