apprtc/main.js: removed redundant JSHint directives
Minor tweaks to JSHint directives and comments
Added MediaStreamTrack to .jshintrc global
Addition to .jshintrc global array
Changed global to globals as per #159
Merge pull request #155 from samdutton/master

Minor JSHint tweaks: .jshintrc and apprtc/main.js
merge master