Add HasOwnProperty case for IDictionary types
Fix handling of dynamic property access for Array/Vector

Updated the behavior to match ActionScript. Strings representing
integer values are converted to indexed accesses. Strings representing
any other value are dynamic property accesses for Array, and throw
ReferenceErrors for Vector.
Fix handling of in, delete, and hasOwnProperty for Array/Vector

Updated the behavior to match ActionScript. Fixes issue #276.
Fix dynamic function invokes for Vector
Add test case for deleting numeric keys from Dictionary

This is to check for regressions of issue #279
Remove unnecessary cast
Merge pull request #283 from playscript/cbroglie-ps-fixes

Array/Vector fixes