Unquote keyword arg names
Merge pull request #725 from xzyfer/fix/quoted-keyword-args

Unquote keyword arg names
Error if a user defined function uses a reserved name
Should error when trying to string concatenate with null
Merge pull request #727 from xzyfer/feat/reserved-function-names

Error if a user defined function uses a reserved name
Merge pull request #728 from xzyfer/fix/concatentating-null

Error when trying to string concatenate with null