Add simple Color union.
Flip the backbuffer in Display, not VideoBuffer.

VideoBuffer::Flip() now only blits the legacy buffer to the screen, it
doesn't do the actual flip.  Instead, the flip now occurs when the scene
has finished rendering, so that new rendering components can get a
chance to render to the backbuffer.

As a result, any scene that intends to use the legacy buffer must lock
it themselves.
Split rendering phase.

This is mainly so we can profile the time it takes to prepare for
rendering (updating textures, etc.) versus actually updating the
framebuffer.
Add rendering phases to views.
Implement basic rendering for SdlLabelView.

This is a very rough initial port of the code from StaticText.
Add "Palette" title label.

This is mainly to have *something* to test the Label component for now
:)