Fixed clone command line for installing mobifyjs
Fixed clone command line for installing mobifyjs

`git checkout https://github.com/mobify/mobifyjs.git` doesn't work on a non-repo directory:

```fatal: Not a git repository (or any of the parent directories): .git```
landsurveyorsunited/mobifyjs,landsurveyorsunited/mobifyjs,landsurveyorsunited/mobifyjs