this function was transforming "no" and even 0.0 (floating point number) to nil.
That behaivour was incorrect for numbers and probably not desiderable
for the string no (in fact poll with "No" option was not rendered
beacause of this fact).
Removed conversion for non- integer numbers and prevented conversion
from some kind of non empty string (like "nil" or "no") via a key
argument.
- renamed function: 'text-utils:left-padding-suffix' to 'text-utils:left-padding-prefix';
- rendered the choice index for poll's choicehs;
- shown if a poll allows multiple choiches.
