Change "foreach" statement behavior (this is just a PoC yet)

Change "foreach" statement behavior (this is just a PoC yet)

- "foreach by value" don't relay on internal array/object pointer and doesnt perform array duplication. It just locks it incrementing reference counter. If the original array is modified by some code, the copy on write is performed and "foreach" still work with the old copy.

- it makes no difference if array given to "foreach by value" is reference itself

- "foreach by reference" still use internal array/object pointer and should work similar to PHP-5. (This id not completely implemented)