observe.sort -- Fix build process

Fixes build process.  Steal doesn't seem to like a regex next to a uniary plus.
Make Observe.List.push() still trigger 'add' event if comparator is set, but sort plugin is not loaded.
Merge branch 'master' of https://github.com/schmod/canjs
Merge pull request #290 from schmod/master

Observe.List.sort -- Fix build process