Code styling fixes:

-   For all <pre> blocks, allow horizontal scrolling
    instead of wrapping text.
-   For side-by-side element in tutorial, keep code
    block from stretching vertically.
-   Use link color for <a><code>. Nesting <code><a>
    already works, but is error-prone; this just ensures
    we use the right color either way.
Removed commented-out property.
Add primitive analytics for site search.
Merge pull request #532 from arthurevans/tutorial-codeformat

Code styling fixes
Fixed usingelements.md paper elements link

A link stated that it pointed to paper elements docs but instead pointed to core elements docs. Fixed so that it points to paper elements docs.
Merge pull request #536 from wclear/patch-1

Fixed usingelements.md paper elements link
Added TODO note to move analytics out fo global scope.
Update license
Add limit to concurrent grunt task
Update databinding.md

Some of the mustache brackets aren't consistent, just a little change.
P.S. the same is also in the code snippets but i can't change them because they are PNG files.
Merge pull request #533 from arthurevans/search-analytics

Add primitive analytics for site search.
Update binding-types.md

Add missing space
Merge pull request #538 from vmarasow/patch-1

Update databinding.md
Merge branch 'master' into perf

Conflicts:
	css/site2.css
Merge branch 'perf' of https://github.com/Polymer/docs into perf

Conflicts:
	_includes/footer.html
	css/site2.css