Actually include colon in header response.

If we’re copy/pasing headers from the display into the "tweak the headers" form, it’s nice if we don’t have to re-add the colon (this was the effect since we were using css after elements).
Fade out the response when another is made.

Instead of just deleting the content from the screen, let’s fade it out quickly. It looked a little harsh before.
Don’t show “force reload” when in a textarea.

When we’re editing the response headers, sometimes I use ALT+Arrows to select words at a time. This was a little distracting, because the “Force ” was show/hiding in the background.

This commit prevents the ALT+Click to force request when the textarea is open — no big deal, since we can’t actually click that when the dialog is open anyways.
Misc. visual tweaks.

Just a bit of rounding out rough edges.