Make DateInputWidget use a simple text field (Pylons/deform#101)

[rbu]

input[type=date] is now supported by modern browsers and displays a
native date picker. This makes sense for a native widget, but opens two
datepickers when the jquery UI datepicker is added. Revert to type=text
for now.

[rbu]

issue #101

[kiorky]

Maybe it would be better to fix the original issue ?

[tonthon]

Note : The jquery datepicker allows much more customisation than the browser's widget (through the altField).

[rbu]

@kiorky, the only way I know of to avoid using the native date picker in modern browsers is not to use input[type=date]. What do you mean by original issue? My patch makes this a "no native" date input, the other solutions I see are making it a "native only" input that has no fancyness in old browsers or making it a "native, if available" input which requires support from the jQuery UI datepicker and has its own problems (such as users seeing different pickers ond different devices).
There could be an option for a deform user to choose between these, and the patch simply provides the first choice.

[ppaez]

The solution in pull request #142 was merged.