Remove redundant using and propery naming cleanup
Delete redundnant variables
Remove redundant qualifiers
More cleanup to improve readbility
Remove StackFrame.GetAt()
Add RuntimeMemory.GetStackFrames()
Make StackFrame.SetAt() private
Remvoe GetStackFrames()
Restore two debugger related functions
Merge pull request #2552 from ke-yu/mark_and_sweep

Code cleanup for executive