[Form] Add "range" type

[analogic]

There is missing support for "range" html element: "Could not load type "range""

http://www.w3schools.com/html/tryit.asp?filename=tryhtml5_input_type_range
http://caniuse.com/#feat=input-range

[LewisW]

Does this really deserve its own dedicated form type, or could it be an option in the integer and number types. The range control is very similar in terms of functionality and behaviour as the number control. It's just really the UI that's different.

Likewise, is it for implementing the other HTML5 inputs into Symfony Core as their own field types?

[crevillo]

+1 for the option insted of the dedicated form type as @LewisW says. I'm on the hackaton in Madrid and gonna try to do this. @javiereguiluz @weaverryan