New landing page content.
Updated PDF.js.
One more time, PDF.js version update.
Updated landing page content and formatting.
Fixed spacing in index.html and _index.style files. Added arrow icon.
Fixed formatting and edited content for clarity.
Moved all formatting to CSS.
style fixes
Fixed arrow image relative path.
Merge pull request #148 from peerlibrary/new-landing

New landing page content and formatting added.
Added AGPLv3 license file.
Fixed dependencies.
Added troubleshooting section.
Merge branch 'master' into upload