Bump of dropzone version to 3.8.2

I've bumped the version of dropzone up to 3.8.2 due to an error I was getting when attempting to drag and drop a file into a designated dropzone area. The error was cannot read property 'isFile' of null. Did a quick google search and it there was an issue (enyo/dropzone#285) which led me to believe the version of dropzone combined with the current version of Chrome was the cause.  It seems to have fixed the problem.

Please note that the css files are no longer scss files, they are just regular old css files.  Not sure if you wanted anything special done here, so I just replaced the files as-is.

All I really did was replace the .js file and the 2 css files and update the dropzone version references.  I have not adjusted the version number fo the gem itself, as I'm not sure if you would actually like to have that done.  If you want me to, feel free to leave me a message and I will do it.