Visualization of top clients and shares by nfs operations

Add new probe view and template for nfs share and client visualization.
Add collapsible tree visualization for nfs client and share
visualization.
Add styles for visualization.
NFS activity for shares and clients

Add timestamp to probe data url while fetching data
Dont empty probe content area on probe stop
Style changes for probe content
Merge pull request #158 from sujeetsr/issue#114_top_shares_clients

Issue#114 top shares clients