PyCXX V6.2.8 released

[Barry S. <ba...@ba...>]

Version 6.2.8 (10-May-2016)
 * Fix crash when a member function is called via callMemberFunction() and 
that function raises an exception.
 * Found in comment on StackOverFlow. Fix memory size allocated for new 
objects. It used the wrong size calculation, but was big enough to avoid 
problems.