Revert "Increase $XS::Typemap::VERSION to 0.13"

This reverts commit 3407f4a92d7d9731d099e0290b68d7e983ff2497.
Revert "Squash COWs in the char* typemap"

This reverts commit 77ca9de6373481d905eed6af2904599353a658b3.