-adjusted layer purpose numbers according to layer properties from sg13g2.lyp
-verified sealring against virtuoso Pcell layout counterpart
-introduced stack-based PyCell-contexts for hierarchicaly layouts
-added partial implementation for PyCell-API class Instance
-added partial implementation for PyCell-API class ParamArray
-added API documentation stuff, updated pdf documentation
-added support for layer-properties read from lyp-files
-added support for npn13G2
-adjusted layer purpose numbers according to layer properties from sg13g2.lyp -verified sealring against virtuoso Pcell layout counterpart -introduced stack-based PyCell-contexts for hierarchicaly layouts -added partial implementation for PyCell-API class Instance -added partial implementation for PyCell-API class ParamArray -added API documentation stuff, updated pdf documentation -added support for layer-properties read from lyp-files -added support for npn13G2