Suggested docs additions/modifications

[mattfelsen]

• show example of using std::bind instead of lambdas for signal callbacks
• example of event dispatch system - both dispatching & receiving
• note on subclassing BaseViews says you'll override update or draw, but it's just as likely to not override and instead only manage child views via callbacks (child tapped, animate this, etc.). Update docs to reflect?
• keyboard shortcuts used

[benjaminbojko]

This is super helpful, thanks @mattfelsen