Give the inlineEditor widget a "raw value" option.

When we use the inline editor today, we take the contents of whichever element
is set, strip out any HTML formatting (like links that we may have inserted),
and then set that as the contents of the input widget. This is insufficient if
we want to do things like format things with markdown.

This change adds a couple options, hasRawValue and rawValue, to the widget. If
these are not set, everything works as before. If hasRawValue is true, the
contents of the rawValue option are used as the source text, rather than
calling .text() on the element and stripping it.

Testing done:
Used this with both raw-value and normal inline editors. Saw that my original
text was visible in the former, even after markdown changed things a lot, and
that the latter behaved as before.

Reviewed at https://reviews.reviewboard.org/r/4484/