Openslide-python

* Change default Deep Zoom tile size to 254 pixels
* Fix image reading with Pillow 3.x when installed `--without-performance`
* Fix reading ≥ 2²⁹ pixels per call `--without-performance`
* Fix some `unclosed file` ResourceWarnings on Python 3
* Improve object reprs
* Add test suite
* examples: Drop support for Internet Explorer \< 9

* Improve pixel read performance using optional extension module
* examples: Add scale bar via OpenSeadragonScalebar plugin
* examples: Update OpenSeadragon to 1.2.1
* examples: Enable rotation buttons in multiserver
* examples: Verify at server startup that file was specified
* examples: Disable pinch zoom outside of viewer

* Fix documentation build breakage

* Add documentation
* Switch from distutils to setuptools
* Declare Pillow dependency in `setup.py` (but still support PIL)

* Fix breakage on Python 2.6
* examples: Fix tile server breakage on classic PIL

* Require OpenSlide 3.4.0
* Support Python 3
* Return Unicode strings on Python 2
* Replace `OpenSlide.can_open()` with `OpenSlide.detect_format()`
* Optionally generate Deep Zoom tiles only for the non-empty slide region
* Fix Deep Zoom tile positioning bug affecting Aperio slides
* Fix library loading with MacPorts
* Propagate open errors from `openslide.open_slide()`
* examples: Add multiple-slide Deep Zoom server
* examples: Enable multithreading in tile servers
* examples: Avoid loading smallest Deep Zoom levels
* examples: Update OpenSeadragon to 1.0.0