Moved JintRuntime into the Native namespace.
Implemented JsBox as the container in the code generator.

This is a temporary step to using object as the type.
Compile method into a real assembly.

Switched from lightweight dynamic methods to real assemblies with a performance improvement of 60%. The difference between raw code (decompiled from a saved assembly) and from JavaScript source is now 10ms on my machine, which is all the overhead of the compiler and jitter.
Made ArrayPropertyStore sealed.

5% performance gain...
Fixed failing unit tests because of conversion to JsBox.