* Added a "menu toolbar" to the top of the Edit Mode with useful buttons
that work: New Level, New Doodad (same thing), Save, Save as, Open.
* Added ability for the dev console to prompt the user for a question,
which opens the console automatically. "Save", "Save as" and "Load"
ask for their filenames this way.
* Started groundwork for theming the app. The palette window is a light
brown with an orange title bar, the Menu Toolbar has a black
background, etc.
* Added support for multiple fonts instead of just monospace. DejaVu
Sans (normal and bold) are used now for most labels and window titles,
respectively. The dev console uses DejaVu Sans Mono as before.
* Update ui.Label to accept PadX and PadY separately instead of only
having the Padding option which did both.
* Improvements to Frame packing algorithm.
* Set the SDL draw mode to BLEND so we can use alpha colors properly,
so now the dev console is semi-translucent.
* The shell now supports an "eval" command, or "$" for short.
* Runs it in an Otto JavaScript VM.
* Some global variables are available, like `d` is the Doodle object
itself, `log`, `RGBA()` and `Point()`
* The shell supports paging through input history using the arrow keys.
* Added an initial Main Scene
With Labels and Buttons so far.
* Labels are pretty much complete, they wrap a render.Text and have a
Compute() method that returns their Width and Height when rendered
onto an SDL Surface.
* Buttons wrap a Label widget and Compute() its size and takes that into
consideration when rendering itself. Buttons render themselves from
scratch in a "Windows 95" themed way, with configurable colors, border
widths and outline.
