Hi everybody,
some days ago I found a browser made especially for developing and testing websites, named ‘Blisk’.
Some infos about it:
- it emulates many popular devices (phones, tablets, etc.) and shows a mobile version of your website next to your desktop version
- page auto-refresh on change of sources
- screenshots & -recordings
- integrates w/ bugtrackers
- powered by chromium
- free
- …
I like it pretty much and I beliefe some of you will love it, too 
~N