Describe template variables
Ignore setup.py's build/ directory
Fix exif/raw_exif and add datetime documentation
PEP8ify
Include README.rst in index.rst

This reduces redundancies and potential inconsistencies between the README and
the main docs.
Add AUTHORS
Merge pull request #26 from matze/update-docs

Describe template variables
Merge pull request #27 from matze/misc-cleanup

Miscellaneous changes
Set `zip_gallery` only when one is available

This change introduces a new variable `zip_gallery` to the Jinja context. It is
only set to `settings.zip_gallery` if a directory has a zipped archive.
Add documentation for `zip_gallery`
Merge pull request #28 from matze/fix-zip

Set `zip_gallery` only when one is available