Remove redundant namespace prefix
Change IsEqual() method to override Equals()
Remove unnecessary assert; change NodeUpdateRef.IsEqual to Equals
Change SymbolNode.IsEqualAtScope to SymbolNode.Equals
Minor cleanup
Push string index into dimension list of grpah node
Add a regression test case
Merge pull request #2187 from ke-yu/fix_array_indexing

Fix that array indexing cause dependency to be broken