Update mtr for Mavericks compatibility

* Switched Site and URL values in the makefile; github might effectively
  be the homepage now, but it isn't where the released version source is
  distributed from.
* Updated Source pattern accordingly, to match the release .tgz from the
  website
* Added a small patch which enables the 0.85 release to build on
  mavericks.
Merge pull request #42 from jamezpolley/master

Update mtr for Mavericks compatibility