datepicker js: default to `inline-block` for wrapper display
datepicker js: default to `inline-block` for wrapper display

This updates the datepicker js to default to `inlin-block for the
wrapper's display.  The detecting via css approach is just too
unreliable.

In addition, you can now override this default with the
`data-romo-datepicker-elem-display` data attr.

redding/romo,redding/romo,redding/romo