Hugophotoswipe

- Fix for "input" on Python 2.

- Don't sort photos when writing to YAML (fixes 22).

- Fix issue 17, bug in cover image path on Windows

- Update versioning scheme to major/minor/hotfix. In the future the last field
will only be used for hotfixes, the minor field for small changes and
features, and the major field for backward-incompatible changes.
- Extend unit tests for ``Photo.resize_dims()`` to catch the bug fixed by
version 0.0.16.
- Added some documentation to the classes and methods

- Hotfix for ``resize_dims`` for Python 2, where round returns float instead
of int.

- Changed ``dim_max_`` settings to using a string input field which can take
different size specifications. This allows for setting constant width,
constant height, or specific size of photos. Updated the documentation to
reflect this change.
- Removed the now obsolete ``square_thumbnails`` and ``square_coverimage``
settings
- Added unit test for the ``resize_dims`` method of the ``Photo`` class.