Replace ESCAPE by DOWN key to re-show picker

Replace ESCAPE by DOWN key to re-show picker.
Why?
First, ESCAPE means CANCEL or CLOSE, and it seems weird to display a picker on cnacel.
Then, to be compliant to components like SELECT, DOWN key diplays slector and ESCAPE just hides the SELECTOR
Then, there is a modal behavior issue, and specifically in a modal. Scenario : 
- open a modal
- in this modal to fill some data
- in thi modal you open a picker to select a date
- you press ESCAPE to cancel your date choice
- at this point, with the current implementation, you get an undesired behavior : the modal is closed, so you lost all data of the form instead of a closed picker only.