Fixes to supplied macro and other enhancements

[jeremydw]

• Support for textarea descriptions/placeholders.
• Add support for input field next to "other" checkbox.

[jeremydw]

POST data for "other" checkboxes looks like:

entry.1810603989_sentinel:
entry.1810603989.other_option_response:OTHER TEST
entry.1810603989:__other_option__