a Models class that governs all other models: persistence, presentation, and validation.
a standard CRUD code using models and token.
ignore dreamweaver’s dwsync.xml files.
add setter for injecting dependencies.
add getter for injected objects, and some useful methods.
should return the primary key when inserting a datum.
introduce EnumArrayInterface.
error message is added by Datum class.
not to pass error message to $sel object.
findById uses DaoBase’s findById.
DaoBase should be responsible for escaping inputs when insert/update db.
should use dao’s quote  method to quote data for sql in insert/update.
Merge branch 'classes'
renamed some classes and methods, hopefully, to clarify what they are.
try to make Model less active-record-like.
include interface before it is used in other classes.
Datum to use code/list values from Enum objects.
入力確認のための修正。
古いpggに合わせて定義を変更。
maybe a generic message class.
How about a small Dio class to transfer variables from one page to next.
modified so that old old old pgg_check can work.