They can use the remove vote button or select the same option again for
single choice polls.
This commit refactor the plugin to properly organize code and make it
easier to follow.
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
Bianca Nenciu
Jarek Radosz
Mark VanLandingham
Sam Saffron
Régis Hanol
Guo Xiang Tan
Guo Xiang Tan