Change linting options to allow function hoisting

Change `latedef` to `false` so that jsHint doesn't complain about
function hoisting.
Do not overwrite mainConfigFile setting if present
preserve media attribute
Merge pull request #96 from necolas/jshint-function-hoisting

Change linting options to allow function hoisting
Merge pull request #106 from louisremi/keep_media

Preserve media attribute
Merge pull request #102 from Andrexen/master

mainConfigFile setting should not be overwritten if already present in requirejs config