Update all examples to use sbt-mu-srcgen

[cb372]

This is what we recommend for real apps, so we should demonstrate it in the examples.

Currently most of the examples use hand-written Scala code for their protocols. Some also have IDL files in their resources directory but they are not used for anything.

[dmarticus]

I'm going to tackle this once all the changes for higherkindness/sbt-mu-srcgen#38 are out; since it'll affect how I use the sbt-mu-srcgen plugin.