Photos-picker

* Tag as stable version

* Normalize doctrings
* Allow Python3 compatibility
* Fix resize filter
* Add make dev command
* Add functional tests
* Mention the possibility to create custom pickers, filters or uploaders in README

* Fix crash when resize filter width has the same value as resize filter height

* Fix errors 404 on README links on pypi.org
* Disable Codecov comments in pull requests
* Allow to use "~" in search paths/excluded patterns
* Replace `excluded_paths` by `excluded_patterns` in documentation

* Set README content-type in `setup.py` for being correctly displayed on pypi.org

* Update usage examples: only catch photospicker AbstractException for displaying exception message
* Add CHANGELOG.md
* Add SmartPicker
* Take care that photos to retrieve count is not greater than total photos count (at AbstractPicker level)
* On FilesystemUploader, check that target directory exists and is empty before scanning
* Add code coverage when running `make test`
* Allow to specify an order for retrieved photos
* Replace :return by :return: on docstrings