Remove genericity from pattern matching example.

This simplifies the example, as the reader is not
distracted with the type parameterization (which is
non-obvious due to covariance).
Don't show nightly builds until the symlinks are fixed.
Simple link to nightly builds directory
Merge pull request #94 from sjrd/proposal/simpler-pattern-matching-snippet

Remove genericity from pattern matching example.
Fix typos in what-is-scala.md
Merge pull request #97 from myfreeweb/patch-1

Fix typos in what-is-scala.md
fix links in hacker guide and various typos.
Merge pull request #98 from gourlaysama/fix/typos

fix links in hacker guide and various typos.
Make more pages validate, this should be most of them.
Fix tag in license.md, see below.

- Jekyll was optimizing <span class="current-year"></span> to
  <span class="current-year" /> which is invalid.
- Because it was invalid, browsers (and the validator) were treating it
  as a <span> start tag. Because of this, when the text of the span was
  set via javascript, some of the copyright info was being lost.

So instead of
"Copyright (c) 2002-2013 EPFL, Lausanne, unless otherwise specified. \
All rights reserved."

We were seeing just:

"Copyright (c) 2002-2013"
Make hacker-guide valid.
Adding Scala Puzzlers to community powered resources
Add a small script to check validation of _site/
Merge pull request #102 from nermin/master

Adding Scala Puzzlers to community powered resources
Added http://scalatutorials.com/tour

Adriaan suggested it, hope it's ok!
Merge pull request #109 from eranation/patch-1

Added http://scalatutorials.com/tour
Getting rid of unnecessary 'contents' heading on feeds
Merge branch 'master' of github.com:scala/scala-lang
New course announcement
Added link to Typesafe training