iOS 5 CFI Assertion Parse Fix

The stream.ignore appears broken on the iOS 5 c++stdlib and moves past the end of the stream when ignoring up to the closing bracket.  iss.eof() ends up set to true.

Changing it to a loop fixes the issue for iOS5 and still works correctly on iOS6.  I don't usually code in c++ so if there is a more idiomatic way to fix the issue please let me know.