add operator T_FOREACH

* show exception foxway as string
* fix double variables '$bar' in $code for source 'echo "$foo[$bar]";'
* fix double while without braces

Time: 498 ms, Memory: 24.75Mb
OK (492 tests, 498 assertions)

Change-Id: Id917d91f56f0daef19fa0ee716feba284c35620c