Resolve the return type to correctly determine if the type is a pointer or
reference to a director class.
SwigType_refptr_count_return() recently added as a simpler fix is no
longer needed.
The conventional approach of using the "type" rather than "decl" to
analyse the return type is used instead too.
Issue #1823
This involves properly counting the number of references and pointers in the return
type of a function and only generate unwrapping code if this number is 1.
For template instances some post-processing code is added to fix the 'decl' and
'type' attributes of functions if changed in an unfavorable way during template
expansion.
This commit fixes swig#1811.