RM #1250 Collection node counts

I have fixed the RM#1250 "Collection node counts". To fix this RM I need to do following changes

• Move "check_precondition" function from module's view class to global level within that python file itself, so that module class will use it. 
• Modified "get_nodes" function of each module's class, run the sql query to count the number of objects and pass the count to "generate_browser_collection_node" function to display the collection count.
• Reuse SQL queries which is used to fetch nodes. Make that query as inner query like "SELECT count(*) FROM( <node's> query  ) AS collection_count". For that I'll have to remove semicolon's from some of the SQL queries.

One case is not handled with this patch and that is on "Refresh" of collection node, count is not updated. If user refresh the parent node then it will be updated. I'll create a separate RM for that.

Attached is the patch file. Please review it and let me know the review comments.           
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