Fix EvalCall() on new expressions when the target has no 'type' key.
Fix a typo in CalcValue().

The 'op' variable was missing the 'a:' prefix.
Merge pull request #6 from igetgames/fix/eval-constructor-function

Fix EvalCall() on new expressions when the target has no 'type' key.
Merge pull request #7 from igetgames/fix/CalcValue-typo

Fix a typo in CalcValue().