Get this building on recent Rust 0.13 nightly builds.

Also, as it's a Windows project use more Windows toolchain, and a more
blatant .ico for the example (from the Rust installer exe)
Fix Markdown in the readme
Tweaks and fixes

Make the examples PSakefile idempotent
Remove a spurious test in the main windows procedure
Implement `Show` for `Font`
Derive Copy where it was automatically before
Expose some more API for drawing operations