Payment fails for product with quotes in the name

I'm getting card validation failures on checkout and watchdog messages like:
Raw CIM response: Reference to undeclared entity 'ldquo'.

One of the products we are using has quotes in it, which aren't being escaped properly before being added to the XML and sent to Authorize.net. Attached is a patch to fix this issue. You may or may not have trouble applying this patch because we are using a patched version of uc_cim.