Custom text on "Continue" widget and/or variation on "multiple choice" widget that's buttons. about oppia HOT 3 CLOSED

p.s. I broke the issue submitting system, I think by having a question mark in 
the text of the issue. It said something like "labels containing ? must have 
additional information" and the submit button was disabled.

We can do the former, by adding a customization option to the Continue widget. 
I was thinking that we needed something like this too.

(Partially) fixed in commit b2873800d180

https://code.google.com/p/oppia/source/detail?r=b2873800d1807fea6b89694e8ba95770
d8cde32d

This fix allows the text on the 'Continue' button to be changed to custom text 
entered by the exploration creator.

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I think that, if we want to have multiple buttons, then this should be a 
display option on the multiple choice widget.

Yana, if you still want the option to customize the way choices are displayed 
(either buttons or radio circles), and expect that this flexibility would 
outweigh the increased complexity of an additional customization option, please 
feel free to reopen this -- probably in a second bug. It's very straightforward 
to add, but I don't have a good feel at the moment for where the balance tips.