Tutorial rework

[wbamberg]

This branch includes structural changes to the SDK documentation as well as lots of new tutorial content. Because there's a lot to look at, I'll ask for review of the various pieces in separate bugs.

[Gozala]

I'm not sure it's useful to mention window.alert as most browsers today have console.log anyway, maybe it's even better to mention that it's just like browsers console.log but logs into different location.

[Gozala]

@wbamberg cool stuff, I'm really excited to see all these tutorials as they cover most of the questions raised by people. I made few remarks in pull request and have some general suggestions:

• I think it would be so much better if we had example add-on's for all these tutorials so users could always look at them. I don't know if we should dump them to examples folder, have separate repos or publish them to builder but either way I think it would be super helpful.
• I found mix of markdown and html markup bit confusing, also I might be missing something, but I think most of a, il, pre tags can be replaced by markdown.
• There is one more question that is raised on mailing lists and IRC over and over again, so I created a bug for it:
  https://bugzilla.mozilla.org/show_bug.cgi?id=734201
  I think it can be a separate task.

Thanks & looking forward to see our users reactions!

[wbamberg]

@Gozala thanks, and thanks for your review of this huge PR! I agree about examples, and I'll raise a separate bug about that. We've discussed this before, and I think the Builder is perhaps the best way to go.

About mixing Markdown and HTML: I try to keep to Markdown, but there are cases where I need to use HTML: for example, because I can't have class or name attributes with Markdown, or (apparently) because I want to include markup inside an element, like DIV or TABLE, that itself has to be specified using HTML directly. So we will inevitably have a hybrid. Still there probably are some HTML elements that could be MD, and I'll scan the patch before landing it.

[Gozala]

We've discussed this before, and I think the Builder is perhaps the best way to go.

only problem with builder you won't see the file paths, but it may be not such a big issue.

About mixing Markdown and HTML: I try to keep to Markdown, but there are cases where I need to use HTML: for
example, because I can't have class or name attributes with Markdown, or (apparently) because I want to include
markup inside an element, like DIV or TABLE, that itself has to be specified using HTML directly. So we will inevitably
have a hybrid. Still there probably are some HTML elements that could be MD, and I'll scan the patch before landing it.

Right I have not thought about that.

[Gozala]

@wbamberg do you still wanna keep this pull request open ? If no could you please close it ?