fix(cookie cutter): fixes the misuse of `repo_name`/`project_name`

* project_name may contain spaces, do not use for generating emails
* 'name' variable in package.json is used by Gruntfile to figure-out
   the directory structure of project, so `repo_name` is what must
   be used here
Merge pull request #92 from theskumar/fix/cookiecutter-variable

fix(cookie cutter): fixes the misuse of `repo_name`/`project_name`