Until the Go core team include support for generics in Go, genny is a
code-generation generics solution. It allows you write normal buildable and
testable Go code which, when processed by the genny gen tool, will replace the
generics with specific types.

  * Generic code is valid Go code
  * Generic code compiles and can be tested
  * Use stdin and stdout or specify in and out files
  * Supports Go 1.4's go generate
