Developer tools: grunt-patch-wordpress from jorbin, for applying patches directly from Trac.

Mapped to `grunt patch`, which declares usage. Requires `npm install` to install.

props jorbin. props helen, evarlese for help with grammar/instructions.
see #27023.


git-svn-id: https://develop.svn.wordpress.org/trunk@27299 602fd350-edb4-49c9-b593-d223f7449a82