Code:
  * Test mutant with dynamically created zombie.
  * Fix ugly code within default parameters

AST:
  * Fix the rubinius AST to allow setting @vcall_style variable in Rubinius::AST::Send nodes.

Mutations:
  * Add some kind of a "do not touch me object" that raises on all messages.
    It can be used to make sure each literal value is touched.
  * Replace nil or add "do not touch me object" to literal mutations.
  * Mutate options on Regexp literals
  * Add mutations for dynamic regexp symbol and string literals
  * Mutate "def foo; bar; end" to "def foo; self; end"?

Loader:
  * Make sure loader does not change visibility of injected mutants

Killers:
  * Aggregate warnings on missing spec files
  * Add a general master <=> killer IPC interface. So different strategies of isolation 
    (fork, vs jruby runtime creation) will work without big impact.

Matcher:
  * Allow matches on attr_reader with literal name argument(s)?
  * Allow matches on define_method with literal name argument?

jruby-support:
  * Hook melbourne via ffi
  * Create a runtime per mutation to kill mutations in isolation