changed the location of the karma.conf.js.example from sandbox to test
changed references to the file location in .gitignore and CONTRIBUTING.md and Gruntfile

testing:
verified that the .example file is picked up by git status and add (per this commit)
verified that any conf.js files are ignored if they are in the test/ folder
verified that with the new location of the karma.conf.js file in Gruntfile, that the tests run as expected