Merge pull request #344 from MuMech/dev

MechJeb 2.2.1 release
Merge pull request #345 from MuMech/dev

MechJeb 2.2.1 release, now with the proper DLL version
Add an override for the Docking AP safe starting distance
Revert "Add an override for the Docking AP safe starting distance"

This reverts commit 9ad63752a60267955f19dd2f11d58be7a2e232e5.
The Makefile is now OSX and Linux aware
Fixed the Linux path
Merge pull request #381 from olasundell/master

OSX-aware Makefile, now with correct Linux path and correct branch.