Text metrics in the diagrams backend are now returned correctly.
Moved the cairo specific test stuff to separate file.
The tests on real charts now also run with the diagrams backend.

I split them up so they can be run with either backend.
They are not completely correct yet.
Removed test dependency on cairo backend.

None of the tests has a main function anymore, because of this.
Added fonts that will be included with diagrams backend.
Implemented the default fonts to be used by the diagrams backend.
Fixd some module export issues and implemented that the diagrams backend actually uses its own fonts.
Updated tests with the changes in the diagrams backend. Environment have to be created using IO.
Fixed issue with different font output size in cairo and diagrams.

The metrics in SVG fonts do not seem to match with the definition of the
metrics deliverd by cairo. I now calculate the metrics in the diagrams
backend such that they match the definition of cairo (95%).
Added a test that renders a font using diagrams/cairo and cairo side by side to compare their sizes.
Chart: Port to lens

Most of these changes were just flipping around underscores. This was
mostly accomplished by,

  %s/\([a-zA-Z0-9_]+\)_\([^a-zA-Z0-9]\)/_\1\2/c
chart-cairo: Port to lens
chart-diagrams: Port to lens
Renderable: Use makeLenses to create lenses
chart-tests: Port to lens
chart: Update comments and documentation for lens
Add lower bounds on lens
Merge pull request #2 from bgamari/lens

Port to lens
Reset Makefile to use cabal-dev, and tweak for ghc-7.6.3
Updated version to 1.0!