Remove unbound variable warnings

Remove unbound variable warnings that were resolved at runtime
Resolve conflicts
Shorten temp variable name
Ask users to save their unsaved work before open a new one
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into fixwarnings
Code refactor

1. List->Hashset
2. Rename symbol to be more descriptive
Updated as feedback
Merge pull request #3030 from ke-yu/fix_long_temp_var

Shorten temp variable name
Merge pull request #3031 from theanh0512/DropFileOnStartPage

Ask users to save their unsaved work before open a new one
Added Test cases for DEfects those were related to Geometry.
Added more information to Test Case related to Defect.
Merge pull request #2989 from junmendoza/fixwarnings

Remove unbound variable warnings
Merge pull request #3032 from riteshchandawar/GeometryTestsFromDefects

Added Test cases for Defects those were related to Geometry.
Resolve conflicts