Documentation request: tips for installing custom extensions

[vegardinho]

I had not previously installed a custom extension, and struggled quite a bit getting things to work. Although I wouldn't expect a full-length tutorial on this, a few tips would spare newcomers like me a ton of time:

• A recommendation of the easier browsers to develop/install extensions on.
• Links to relevant help/tutorials.
• Tips on a few obstacles that are sure to occur for most people. It took me hours to realize that my logs weren't showing up because they only showed up in a separate window for extension-exclusive logs.