Fix build against V8 >= 3.24.4

hey there,

here's the promised pull request to fix the build against the most recent V8 versions.

The first commit just fixes the build, but would break with all V8 versions before 3.23.12, which is just a few weeks old.  Hence I decided to add three more patches with some #ifdef to achieve compatibility back to version 3.22.3, which was released on September 27, 2013

This is V8 version 3.21.12 up to 3.22.2 aren't supported any longer once this is merged.

cheers
  stesie


This fix closes #81