Fixed position nav & question panel, iconify nav.

Making the question bank fixed position should be more convenient for
adding questions as users can just scroll to the question they want, and
then scroll to the section of the form they want, then just drag and
drop the questions in. It also fits well with the fixed position top
navbar.

Note that because there's no way for css to properly deal with fixed
position in a responsive manner and because bootstrap won't let me mix
fixed width and responsive width columns, I had to style my own fixed
width sidebar with a responsive main content area.

The print button was moved to the top navbar. The top navbar now has
icons instead of text buttons.
Allow questions to be removed from form.

The button to remove individual questions from the form was added in the
previous commit but it was non-functional due to a missing controller
counterpart. This commits fixes that.
Sidebar responsive height, highlight, controls.

Sidebar's responsive height now increments by the number of questions it
can display. This was done by trial and error, so hopefully it works
well enough in most browsers.

Each question will now highlight when user hovers over them. When
dragging questions, the drag icon will maintain the same appearance as
when a user highlights it.

One additional button was added for users who don't want to click and
drag questions to the form, they can click this button to send a
question to the form instead.

Due to the additional button, the question controls were placed into its
own ul for proper positioning.

The question control buttons has a less subtle hover effect now, the
previous one seems to be too easily missed.