Fix #6: Add syntax highlighting to code snippets.
Add scala-js-resource to the list of Tools

I figure someone else may find it handy at some point; I can't be the only one who's annoyed at the browser's anemic filesystem interface
Merge pull request #18 from lihaoyi/patch-2

Add scala-js-resource to the list of Tools
Added Scala.Rx and uTest to index.md

Just announced them, and although I haven't published Scala-JS maven artifacts for them yet, I think people would be interested.
Merge pull request #21 from lihaoyi/patch-3

Added Scala.Rx and uTest to index.md
Update semantics to document scala.Symbol support

Also document that they are a potential source of memory leaks.

Fixes #23
References scala-js/scala-js#234
Document impossibility of catching java.lang.StackOverflowError

Fixes #22
References scala-js/scala-js#212
Document missing support for character sets

Fixes #15
References scala-js/scala-js#177
Change absolute URLs to relative URLs to ease local testing
Merge pull request #24 from jonas/scala-symbol-support

Update doc/semantics to document newly added scala.Symbol support and missing charset and StackOverflowError