Merge pull request #4 from bgamari/master

Fix documentation
Added Eq and Ord instances for data types.
Introduced diagrams backend environment with custom preloaded fonts.
Fixed bug in diagrams backend concerning unclosed trails of a path when filling.
Extended fill test case for drawing operations, so filling of a multi trail path is also tested.
Updated reference image of the drawing fill test.due to changes.
Added a test harness to produce SVG charts
Merge branch 'master' of github.com:timbod7/haskell-chart
Added backend utilities for rendering of SVG and EPS images for the diagrams backend.
Now also exporting the helpers.
Ignore build products.
Fixed the diagrams rendering issue with upside down SVGs.
Moved size of the diagrams backend output into the environment.

Now runBackend also creates diagrams as suspected.
Added utilities to work with custom environments.
Fixed compile errors in the diagrams backend.
Ignore output images in the test directories.
Updated tests to work with the new diagrams backend interface. Also added EPS test generator.
Bumped diagram dependency version in tests and fixed the font compare example.
Fixed rendering error with the font compare example.
Some additional documentation of the diagrams backend.
Merge pull request #7 from jbracker/master

Latest changes before release.