drupal-composer
Set Enable Patching to true
This PR probably does want some thought beyond bug fix... lets merge. This adds 'enable-patching' = true to the extras key. This means that patches from projects will be applied. This is obviously great in many ways but it is a significant change. Example of usage: https://drupal.org/project/field_states_ui is applying a patch to core so as to be able to use a hook that doesn't exist, without killing kittens.
This proved to be very useful for being able to add installation profiles that require core patches. Adding it to my configuration seems to have worked very well. I think that if we find incompatible patches in the future, it is possible to add skip patches configuration on a case by case basis https://github.com/cweagans/composer-patches#ignoring-patches.
I think this simple change should be merged. It makes a lot of sense to allow patches from included composer.json files. If the patch doesn't apply, composer recovers gracefully and ignores it.
