Move Button in to its own 'button` package.
Rename 'sass' directory to 'css'.
Add tests for Component's getWidth/getHeight methods and variants, and fix issue with "outer" width/height argument not being provided.
Fix HBox and VBox layouts to handle hidden components.
Rename LayoutFixture methods getTargetElWidth() and getTargetElHeight() to be getContainerWidth() and getContainerHeight() instead. Makes more sense and easier to understand in tests.
Change doc comment in UI singleton be class `ui.UI`
Add simple border around TextArea fields in basic theme, and remove Chrome's resize feature.
Fix HBox layout to properly size empty Components. Needed to make empty Components have at least 1px of height to take up space with `float:left`.
Add workaround to HBox layout to attempt to take into account sub-pixel widths that the browser is using on elements. Not perfect, but works for now.
Add ability for Panel to take bottom buttons.