feat #429 pattern as inputPattern on datepicker

Allow pattern to behave as input pattern when inputPattern is not defined
This allows to type a date in the same output format without having to
specify it

Close #429 Close #433
fix #467 aria.utils.Json.getValue() returns undefined for value 0

fix it changing the if condition and added a unit test.
feat #460 scroll event handler

Enables the developer to use on scroll event handler in TPL files

Close #460
feat #468 page engine

Contains all source code + tests related to page engine feature.
Closes #468