- Add script injection to vAPI, plus a raw implementation for Safari
(element-picker.js requires it)
- Tweak element picker to work with Safari
- Revert a change from previous commit: element-picker.js' background
message handler (since actually it can have its own messaging channel)
- Don't send "undefined" reponses from background to content
.jshintrc's otion-set is a personal choice, merely a suggestion.
Beside that, it includes some common globals for specific browsers, so
there's no need to set the globals in every .js file.
In order to force strict coding, "use strict" directive was added into
every .js file.
