Cascadenik

* Fixed a bug in setup.py that required README.md to be present when pip-installing.

* Fixed line-dasharray bug: https://github.com/mapnik/Cascadenik/issues/11.

* Updated for Mapnik 2.0.0.
* Replaced `style.stylesheet_rulesets()`, `style.rulesets_declarations()`,
with all-new `style.stylesheet_declarations()`.
* Fixed support for negative numbers in attribute selectors.
* Added Style `filter-mode="first"` to generated XML.
* Switched away from a state machine approach to a generator approach inspired
by Eli Bendersky: http://eli.thegreenplace.net/2009/08/29/co-routines-as-an-alternative-to-state-machines/.

Version 1.x.x
-------------

* Switched from `os.rename()` to `shutil.move()` in `cascadenik-compile.py`
so cross-device moves would work.

* Fixed use of shield symbolizer displacement based on https://github.com/mapnik/mapnik/issues/947.

* Added `shield-text-dx` and `shield-text-dy` properties.