Scaffolding for exporting from the command line.

I had originally assumed I'd want to package the bash script up with the .air app, but Tim's
convinced me that it makes more sense to keep it separate. My initial concern was that the script
will likely be necessarily tied to changes in the arguments the exporter expects, but we'll just
need to tag the script for releases like we do the .air.
That bidness turned out to be unnecessary.
A better name... no flash app can be truly headless.
Full implementation of automatic (command-line) exporting.
More output feedback.
Collect and communicate uncaught exceptions.
I believe this stage quality thing is useless (and it NPEs)
A couple more error cleanups.
Remove redundant check.
The exportDir conf property is relative to the conf's parent dir.
Wait a frame before doing actual publish.

Publishing always involves a very long frame for any sizable flump project, so let's start it on
a new frame. For one thing, it appears that the output only flushes between frames, and it looks
better from the CL script you've been told that publishing is started before the app halts for
awhile.
Extract some shared functionality to a new super class.

I thought that these two were going to be different enough that a shared super wouldn't make sense,
but there ended up being rather a lot of copied code, so here we are.
Function.length against varags strikes again.
Introduce project file versions and migrations.
additionalScaleFactors -> scaleFactors

This makes the previously implied scale factor of 1 explicit so that it's optional.
Revert "additionalScaleFactors -> scaleFactors"

This reverts commit c7bf86893438e07c9caf5f0aac4e8efe8bfa2020.

This wasn't intended for this branch.
Revert "Introduce project file versions and migrations."

This reverts commit e17fabfa1dfc4c22a8d78eb91993bd7d0a38e429.

This wasn't intended for this branch.
Merge pull request #127 from threerings/command-line-export

Command line export