Accessibility fixes for post editing

This fixes accessibility failures due to missing labels on title and from fields. See the description below from Google's Accessibility Dev site for details:

"Unlabelled controls cause problems for users of assistive technology, as it can be unclear what the purpose of the control is. Particularly in cases where the label is not near the control in the document order, the user may have no way of knowing what the control is for."

https://code.google.com/p/accessibility-developer-tools/wiki/AuditRules#AX_TEXT_01:_Controls_and_media_elements_should_have_labels