rescue for Future
Merge pull request #4 from sythe21/future-result

rescue for Future
Moved string converters to package com.dadrox.scuttle.string from an object that inhabited the same space.
Added filter and withFilter to Result
Added filter to Future
Added Future.withFilter
Minor cleanup of an implicit class
Issue #2 Added a macro that creates information based on where a Failure or Future.fail was created.
Inspired by syteh21's pull request "Macro based tracer"
Made FutureSuccess, FutureFail, and ConcreteFuture private infavor of  Future.success, Future.fail, and Future.apply
Made Enum toString slightly more useful in some cases.
Added a test showing how to do exhaustive match... but every is lazily evaluated, which is not good.
Added a CountDownLatch, which pretty much delegates to a Java CountDownLatch
Fixed a test
Added Duration.Infinite and Duration.NegativeInfinite to prevent over/underflow problems
Removed junit imports
Moved CountDownLatch to the right place
Removed the sbt scala cross versions since scuttle is no longer backwards compatible with scala 2.9.x