change start page's samples list box to treeView. Added show samples in folder
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into treeView
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into treeView
Change some code format, function name
Merge pull request #2294 from theanh0512/treeView

Change start page's samples list box to treeView