Remove event handlers
Release event handler to fix memory leak
Minor cleanup
Shutdown thread in RenderManager
Remove unnecessary event handler removal
Fix error
Remove unnecessary event handler removal
Added test case for syntax highlighting rule for DS digits
Address PR review comments for syntax highlight test
Merge pull request #2555 from ke-yu/Revit2015

Merge pull reqest #2538 into Revit2015
Merge pull request #2554 from aparajit-pratap/Revit2015

Merge from master to Revit2015 branch
Merge branch 'Revit2015' of https://github.com/DynamoDS/Dynamo into Revit2015