[Closes #232, Closes #233] Clean up gemspec.
[Closes #232, Closes #233] Clean up gemspec.

- avoid dependency on git
- variable rename to avoid warning

benizi/tmuxinator,klaxalk/tmux,jlipps/tmuxinator,tmuxinator/tmuxinator,magicalbanana/tmuxinator,sjfloat/tmuxinator,J3RN/tmuxinator,marwensaid/tmuxinator,sachin21/tmuxinator,sideci-sample/sideci-sample-tmuxinator,azat/tmuxinator,J3RN/tmuxinator,marwensaid/tmuxinator,klaxalk/tmux,guyhughes/tmuxinator,pczarn/tmuxinator,benizi/tmuxinator,guyhughes/tmuxinator,ethagnawl/tmuxinator,aMoniker/tmuxinator,tmuxinator/tmuxinator,sachin21/tmuxinator,podung/tmuxinator,cinaeco/tmuxinator,danimad/tmuxinator,jasonchaffee/tmuxinator,jlipps/tmuxinator,sjfloat/tmuxinator,adamstrickland/tmuxinator,klaxalk/tmux,marwensaid/tmuxinator,jasonchaffee/tmuxinator,jasonchaffee/tmuxinator,podung/tmuxinator,guyhughes/tmuxinator,podung/tmuxinator,pczarn/tmuxinator,magicalbanana/tmuxinator,adamstrickland/tmuxinator,J3RN/tmuxinator,tmuxinator/tmuxinator,cinaeco/tmuxinator,ethagnawl/tmuxinator,marcinmagier/tmuxinator,sideci-sample/sideci-sample-tmuxinator,danimad/tmuxinator,sjfloat/tmuxinator,aMoniker/tmuxinator,danimad/tmuxinator,pczarn/tmuxinator,marcinmagier/tmuxinator,aMoniker/tmuxinator,sachin21/tmuxinator,klaxalk/tmux,azat/tmuxinator,adamstrickland/tmuxinator,cinaeco/tmuxinator,jlipps/tmuxinator,azat/tmuxinator,benizi/tmuxinator,magicalbanana/tmuxinator,klaxalk/tmux,ethagnawl/tmuxinator,marcinmagier/tmuxinator