The 0.4.0-alpha0.3 release

• Update golem to v0.1.1 to fix non-power-of-2 textures
• impl std::iter::Sum for geom::Vector
• Implement std::ops::MulAssign, std::ops::AddAssign, and std::ops::SubAssign for Transforms.
• Addition and subtraction of Tranforms supported to help with easing function calculations
• Added an example with loading progress bar
• Add Timer struct to help timing draw calls and a consistent update cycle
• Add exhaust and reset function to timer so they can be used for more than just an update cycle
• lifecycle::run can now accept any kind of Error.
• Add into_raw_context on Graphics, to allow lower-level graphics programming
• Add font support!
  • VectorFont allows you to load TTF files via rusttype
  • FontRenderer allows you to draw glyphs to the screen