use NUMBER_TO_EJSVAL instead of NumberToString here
add a JSON.stringify test
just use @ejs_runtime.array_new instead of a local in visitArrayExpression.  also add an unreachable ir instruction after the call to _ejs_throw to help the optimizer out.
implement Quote, fixes copying environments in the compiler.
add initial regexp support by way of pcre, fix string property access of array indices, and clean up some macros.