Remove <regen> dependency (faster builds)

Since we read all the file metadata for EXIF dates, and we need it as well for the view model,
we should use it to generate the thumbnails and save many calls to glob() and fs.stat()
added gh-pages as submodule
Build the example site into _site (published as Github pages)
README link to the sample website on Github pages
README fix sample website link
Merge pull request #9 from rprieto/fast-regen

Remove Regen dependency (faster builds)
WIP specify options in a separate file