Integrated provenance visualization prototype.
Converted tabs to spaces.
adapted changes for refinery integration
removed debug messages in console
 added some documentation
 fixed warnings
Fixed duplicate event creation issue.
Merge branch 'provenance_visualization_feature' of github.com:parklab/refinery-platform into provenance_visualization_feature
refined node types by adding different shapes/colors
Merge branch 'provenance_visualization_feature' of github.com:parklab/refinery-platform into provenance_visualization_feature
removed selected nodes logic and increased readability for the code
wrapped javascript file into module pattern and edited function call in contents.js
rewritten function declarations as expressions
added type and name to node tooltips
fixed a bug for grouping nodes by layers and added comments
added type distinction for data transformation nodes and analysis attribute in node data structure
added path highlighting; highlight on node-click and remove highlighting by clicking on the canvas
Merge branch 'provenance_visualization_feature' into develop