JavaScript: Added missing static modifiers to avoid duplicate symbol problems with multiple SWIG modules.
JavaScriptCore: Bug fix for finalizer. The finalizer needs to be set on the objectDefinition, not the classDefinition. Otherwise, all the finalize callbacks get NULL back for the PrivateData and can't free the SwigPrivData, causing massive leakage.
Added GDB pretty printers for SWIG types.

This has been extracted from the javascript branch.
JavascriptCore: fix cleanup code.