[INTERPRETER]
* OPT: String routines are now compiled with -O3.
* NEW: Don't display JIT debugging message unless GB_JIT_DEBUG is set to something different from zero.
* NEW: String whose length is greater than 256 now have a growth step of 256 bytes instead of 16.

[GB.JIT]
* NEW: Do many global optimizations as now the class metadata is fully available.
* NEW: Support for optional argument. Still buggy at the moment.