Marker support. perserveAspectRatio Align support
New types/converters for markers and aspect ratio
Finished aspect ratio parser
Fixed ConvertFrom for orient and aspect ratio
Merge pull request #75 from bcbarnes-gmx/Devel

fixed up the support for markers so that they draw properly, and added support for "preserveAspectRatio" except for the 'slice' and 'defer' options.