divide model into two kinds one is using traits, one is using eventize.
new model prototype for two different library.
rough new arch has been tested.
bind unbind has been tested.
remove redundant code.
update values first before connect signals.
new test case was added.
use on_change handle directly, use try except instead of if else.
update from model to view only when bind signals.
test event model in different view backend library.
add error processing code when view update model failed.
avoid update view again and again when value changes.
try to add range check when using eventize as model.
test to see if model would support connect and check at the same time.
test eventmodel with latest eventize packages, which will support Attribute extension.
Range class has been tested as Traits do.
Basic function has been tested in libs. only gtk+traits still has problem.
avoid value type error in traits model.
try to indent value by it's type in definition.
add permission to change convertion functions of model and view, which could supply different convertion strategies to view change event and model change event.
get stable objects from gtk.