Added custom types for line joins and caps.
Swaped usage of LineJoin and LineCap from cairo to custom.
Added a module for the future cairo backend with some smaller utilities.
Removed Cairo from the names of types.
Create custom types for font properties.
Further converts for the new custom font types.
Moved rendering functions that use cairo into the backend module.
Readded the Types module to resolve cyclic dependencies.
Types module now exported.
Resolved errors from moving stuff around. Made abstract CRender based types concrete and unified their render methods in Backend.Cairo
Fixed accessor template haskell.
Fixed export issues and minor compilation errors. Reexported Types and Backend.Cairo through Drawing for the moment.
Removed 'Cairo' from names in other modules.
Fixed incompatible usage of PointStyle.
Fixed all compilation issues resulting from refactoring.
Specialised the exported functions.
First try on a backend interface.
Also export the font extents.