Gamepad rumble

This plugin allow you to make your gamepad rumble through the browser!

Please keep in mind that this is very experimental! 

List of features:

• Compatible with default gamepad plugin 
• Rumble for a specific duration
• Control over the strong and weak mangitude
• Start rumble after a certain amout of time

List of compatible browsers:

• Chrome 65+ (also enable chrome://flags/#enable-gamepad-extensions)
• WIP for NW.js or enable flag manually by entering window.open('chrome://flags/'); inside the console

List of compatible controllers:

• XBOX 360
• XBOX One
• Wii U Pro Controller (Through WiinUSoft (3.3.560 FreshJr Fork) as XBOX 360)

If your device is not listed there, it doesn't mean it isn't compatible. Please test with your device using the test example on this page and let e know. I'll add your gamepad to the list
Sometimes, you need to hit a button on the gamepad to make it appear in the list

Important links:

• https://www.chromestatus.com/feature/5705158763741184
• https://docs.google.com/document/d/1jPKzVRNzzU4dUsvLpSXm1VXPQZ8FP-0lKMT-R_p-s6g
• https://bugs.chromium.org/p/chromium/issues/detail?id=749295
• https://bugzilla.mozilla.org/show_bug.cgi?id=680289

A big thanks to @André for helping me test the plugin!

... this icon is soo ugly ...