2.11 fix

[Arneball]

Fixed

[error] /private/tmp/thyme/bench/Thyme.scala:1499: type mismatch; [error] found : Any [error] required: Double [error] def done(dt: Double) = f"done in ${if (dt>=1) dt else dt*1e3}%.2f ${if (dt>=1) "s" else "ms"}\n" [error]

And

error] /private/tmp/thyme/bench/Thyme.scala:84: in class Thyme, multiple overloaded alternatives of method porder define default arguments. [error] class Thyme(val accuracyTarget: Double = 0.03, watchLoads: Boolean = true, watchGarbage: Boolean = true, watchMemory: Boolean = true) { self => [error] ^ [error] one error found