Allow wildcards in whitelist attributes

[promiselaoliu]

Support validation on data attributes.

[jhy]

I thought this was going to be about wildcards, but it is framed around a new method for data- / custom "data" attributes. attributes. On review of the issue I still lean towards a wildcard match. Like 'data-' or 'ng-' etc. I think that will be more flexible and simpler to use than another method. It can be implemented in the isSafeAttribute method, doesn't need another data structure to retain them,

[promiselaoliu]

I thought this was going to be about wildcards, but it is framed around a new method for data- / custom "data" attributes. attributes. On review of the issue I still lean towards a wildcard match. Like 'data-' or 'ng-' etc. I think that will be more flexible and simpler to use than another method. It can be implemented in the isSafeAttribute method, doesn't need another data structure to retain them,

Fixed.
@jhy