Add bindings for QML

These commits add support for using QHttpServer from QML, which is either awesome or insane.  I'm undecided as to which, but if you think it's the former, here's a pull request.

The first two commits are necessary to get everything working with Qt5.  If you'd prefer, I could split them out into a separate pull request.

There probably needs to be something done to get the QML bindings to install.  I'm new to Qt, so I don't know what that is.  Right now, it will run from the build directory just fine.