Disable submit button on button click to avoid multiple ajax calls

 - Also, add test for the functionality
 - Bump version to 1.2.7

Summary: If submit button is clicked multiple times, multiple
ajax requests are sent. To avoid this, we disable the submit
button as soon as the submit button is clicked and enable it
again at the end of the ajax call depending on the response
from backend. This commit addresses EDUCATOR-273 issued in
openedx JIRA.

survey a11y improvements

avoid numeral-prefixed id attributes; bump to v1.2.5

[template] avoid potential invalid id attribute

[template] forgot to update default label

v1.2.5

dodge a few more numeral-prefixed ids

Added compiled translations

more descriptive labels for survey answers

fix survey a11y test

add col scope to answer heading

add headers to survey td elements

change aria-labelledby to aria-label for radio buttons

fix survey a11y test

Added compiled translations

[template] avoid potential invalid id attribute

[template] avoid potential invalid id attribute

[template] forgot to update default label

v1.2.5

dodge a few more numeral-prefixed ids

ziafazal/WL-580: added translation files and transifex config

Associate poll options with corresponding question

Mcka copy changes

A11y fixes

This commit addresses a11y issues listed in SOL-2059.

Associate survey options with corresponding question and answer

corresponding questions and answers.

[SOL-1996] Ensure header cells are not blank

Blank cells should not be headers for data cells.  Change the upper left
<th>, which is always blank, to a <td>.

SOL-1996

[SOL-1995] Ensure implicit row header cells use th elements

Using th for question cells will ensure that screen reader users will
have the questions announced to them as the move from row to row.

SOL-1995

asadiqbal08/sol 1824 - Complete README instructions for xblock-poll

Remove WIP documentation for working with translations. As mentioned in PR, instructions for working with translations are (largely) the same across XBlocks, so it makes more sense to add them to the 'Internationalization Support' section of the XBlock tutorial.

WL-347 Translations Poll and Survey XBlock

Fix: Results view is too narrow when no images are present

Align radio

Oc/mcka master merge

Fixes for Multiline poll questions.