Add a way to pause the background animation #220

background pause button (version 1)
Add a way to pause the background animation #220

Errors in first pull request generally fixed. However, I split the
footer into two <div>s to create a second row above the default links.
After pausing, the system appears to continue creating new triangles,
but the computational load is now much less intensive.
Add a way to pause the background animation #220

All problems generally fixed, but I changed the right table of the
footer to have two rows instead of creating a separate table, and when
the background is restarted it becomes generally more regular except
for a new progressing wave.
Merge branch 'development' into tiantongqin

merging to make it possible to push to development branch
Add a way to pause the background animation #220

Improved version of background animation pause button. I removed all
<div> tags in footer.html, and there is overlap of text on the home
page. Background should stop updating when the screen animation is
paused. However, after the background is paused clicking on the button
again does not resume background animation.
Merge branch 'development' into tiantongqin
Made pausing work.
Make sure there is no moment when background is black.

In the past while PeerLibrary was loading there were moments when
background was black until animation started. This was not even more
evident with pausing. This addresses this and clears background
immediately, even before animation starts.
Render first background, then cancel if paused.

This allows initial paused background to not be just a blank screen.
Randomized start of the background.
#220: Pause Background Animation

7/18/14 version
Merge branch 'tiantongqin' of https://github.com/peerlibrary/peerlibrary into tiantongqin
Added a section of contributing by reviewing pull requests.
Merge pull request #507 from peerlibrary/tiantongqin

Add a way to pause the background animation #220
Upgraded packages.
Fixed notFound template.
Correctly construct avatar URL in production.

Passing null is not OK because then ROOT_URL is ignored (because option
is passed, as null, instead of not being passed at all).
Add meta data to HTML head

Fixes bug #481.
Merge pull request #564 from nschloe/add-metadata

Add meta data to HTML head
Autofocused username when login form is rendered