Browser settings

Added the ability to modify the following WebView browser settings:
+ Useragent
+ Disable Javascript

I'd also like to add the ability to disable plugins, unfortunately this is difficult due to [deprecated WebView settings](https://stackoverflow.com/questions/19362049/setpluginsenabled-not-exist-for-webview).

One main issue with these changes is that the user agent is a set string. Ultimately I'd like to pull the default WebView user agent from the device and populate the setting, assistance on this would be appreciated (*it's probably easy*)

This is my first contribution to an Android project so please be nice :+1: