Changed mapping folders to mapping sets
Create blueprints for any montage objects
Added the automatic creation of a default blueprint if non exist.
Clean up property descriptors

Fix syntax and some non writable properties serialization.
Remove redundant initialization
Split blueprint files into separate modules.
Simplify super call
Fix syntax
simplify loop to a while
Make _blueprint properties non enumerable
Rename BlueprintBinder to Binder
Merge pull request #1099 from PierreFrisch/blueprint