Glue

^^^^^^^^
* Fix bug with images that only contain digits like. Thanks to Russ Ferriday and Paul Hallett.
* Make possible read optipng related configuration from static configuration files.

^^^^^^
* Added support for multi-dpi (retina) sprite creation.
* New ``--ratios`` and ``--retina`` options.
* New option ``--debug``
* Performance improvements. ~10% on big sprites.

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* New ``--watch`` option to keep glue running in the background watching file changes.
* New option ``--html`` that generates a html using all the available css classes.
* New option ``--margin`` that adds margins around the sprited images. This margin doesn't count as image size.
* Add MANIFEST.in and tune the setup.py preparing the Debian/Ubuntu package.
* Fix _locate_images to be deterministic.
* Add support to Travis CI.
* Fix 8bit B/W images bug.

^^^^^^
* Better error handling: Glue will now return non zero return codes if something goes wrong.

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* Fix ``--version``
* Fix the camelcase ``--separator`` to not lowercase the filename before the capitalization.

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* New feature: Per-file pseudo-class customization.
* Added support for 8bit bg images.
* Added support for digit-only images.
* Fix newline characters support on ``--global-template`` and ``--each-template``.
* New algoritms ``vertical-right`` and ``horizontal-bottom``.
* New option ``--separator``: Customizable CSS class name separator.