Lang.php changes.

Might be time to remove this from the tree and assume automatic compilation of lang from here on out.
Remove some backspace escape issues.
Only compile last lines of special forms when there are enough body expressions.

This allows for smooth compilation of empty class definitions.
Add support for deftype and annotations.
Don't think you're recursive just because you're returning a tail-recursive function.
Restore tmp code holders after checking if a macro is returning a macro.

This code calls ->get_func_name, which can sometimes generate unwanted tmp code even though all we want is the function's name.
Rewrite dotimes to use tail recursion.

*Signficant* speedup compared to mapping over a range.
Modify dotimes test to not rely too much on mutation.