Allow user to pass custom variables to Handlebars.

User can now pass custom variables to Handlebars in the grunt-dashboard config object by passing in a `data` object containing custom variables.
Changed variable from `data` to `userData`
Added documentation for `userData` option.
Bumped version.
Renamed `userData` object to `data`.
Updated `options.data` documentation.
Updated release history for `data` option.
Updated template to use `generated` instead of `data`.
Merge pull request #2 from markbrouch/master

Added ability to pass custom variables to Handlebars template from Grunt task.