2 template directives on the same node

[vicb]

@chirayuk you have reverted 02a5079 because it breaks some applications (in 2b0d9de):

"Though incorrect, it turns out that for common cases, using both ng-if and ng-repeat on the same directive would just work."

If think this is wrong as it could not work as explained in the original issue.

I can understand that throwing an exception is not nice but I'm not sure if a silent bug is better.

Anyways, this defect is here to track the re-integration of the code into the master branch