add support for `ask` pattern

also change Mikka.await_result timeout option
add API for `pipe_to` pattern
sq with pipe_to support
clean up spec

utilizie rspec memoization
operate on actor selections like actor refs
add specs for supervision

note: this commit also changes the duration argument of the supervision strategy constructors. previously, it required an instance of duration. now, it will simply pass the arg to `Duration.[]`
provide shorthand for specifying supervision strategy
add rake as a dependency
add default rake task of running specs
compartmentalize implicit sender support
don't expose ActorRef in Mikka namespace
minor cleanup of method aliasing
add support for using routers
use rspec 2.14.x
add ActorRef/Selection#ask_and_wait
remove deprecated variants of creating Props

Also add support for passing args to the Actor constructor
add helper for getting current routees