Fix encoding warning upon index.php form submit

Whenever we submit a new Sitemap generation task, we get a warning which we should fix.

A form was submitted in the windows-1252 encoding which cannot encode all Unicode characters, so user input may get corrupted. To avoid this problem, the page should be changed so that the form is submitted in the UTF-8 encoding either by changing the encoding of the page itself to UTF-8 or by specifying accept-charset=utf-8 on the form element.

nasa / sitepod

Fix encoding warning upon index.php form submit #3