syncing up styling for disabled button states
Enable/disable save and submit buttons based on input text
Merge pull request #124 from edx/will/enable-disable-save-and-submit

Enable/disable save and submit buttons based on input text
Peer assessment buttons enable/disable
Enable/disable submit button for self-assessment
Merge pull request #125 from edx/will/peer-enable-disable-button

Self/Peer assessment buttons enable/disable
adding styling and markup for submission-based errors
tweaking text-align on step__action messages
Send errors to the DOM
styling response save status UI
adding more padding and visual space for response area
adjusting more padding and visual space for response area
adding styling and markup for step loading-based errors
Merge pull request #126 from edx/will/error-message-ui

Send errors to the DOM
Update save submission tests
Merge pull request #128 from edx/will/fix-talbs-ui-tests

Update save submission tests
adding styling to control toggling appearance of step/submission-based error UI
applying step-based error styling to peer/self assessment actions
applying save-based error styling to response step
JS error message handling