Closing & reopening topic

This will only provide api access for closing/reopening topic,
UI change will be implemented in a subsequent patch

Change-Id: I4001a21856a9e7e044704ee6f42908e09578ddb8
Closing & Summarizing topic frontend changes

Some additional changes:

* For post/topic/header javascript object, $container is moved to the
  corresponding action object, the reason is that the $container for
  each object is dependent on the action; for example, editting a topic
  has a different container than summarizing a topic

* Make generateBlockAction() handle multiple blocks for the same API request

* Optimize all svg images

Change-Id: Iec2a184387a08674afadc92b7d5bd40d7ec2e68c
Merge "Closing & reopening topic"
Merge "Closing & Summarizing topic frontend changes"