Cleaned up Duration for the standard library.

 - Removed Timeout from the library. Each library should provide its own implementation of Timeout
 - Removed duration package object and replaced it with regular object
 - Removed usages of post Java 1.5 TimeUnit members
 - Added factory methods for FiniteDuration
 - Cleaned up some unnecessary comments
 - Merged duration DSL with Duration.scala file

Review by: @phaller
Deprecate scala.parallel.Future and privatize a few classes.
[vpm] test file for regression on old patmat

it's a warning on new patmat -- TODO: dig deeper
[vpm] TODO note: make unapply type list stricter

when an unapply returns Option[T] where T is some ProductN, does that mean the unapply
returns 1 result, i.e., that T, or did it mean to return N results?
to disambiguate, falling back to stricter spec-adherence, which requires T be exactly TupleN for N results

for now, allow extractor result to be any product, not just tuple
[vpm] label-based translation of matches
[vpm] tailcalls support for jumpy vpm
specialize symbols for labeldef params
[vpm] typer synths Function{} for empty-sel match

typedMatchAnonFun is called from typedFunction when the function's body is a match

this is work-in-progres: the compiler currently won't bootstrap under -Yvirtpatmat
see also the pending test

make sure to use the right context in typeFunction when the body is a Match
when typer is set up for type checking a Function, the current owner is the symbol for the function,
but we'll type check a Block(List(ClassDef(cd)), New(cd)) when the function is a match,
and the function symbol is nowhere to be found, so go to outer context

in patmatvirt:
- simplified default case gen (no need for a Casegen instance)
- using CASE | SYNTHETIC to detect generated matches (for switches) and avoid typing them endlessly
  more uniform, and necessary for new-style anon Function class instance gen for matches
[vpm] fix half of my existential troubles

no need for the clunky repackExistential
pack the type of each case instead, since the skolems we've created shouldn't last beyond the case anyway

this way we don't end up with fresh, incompatible, skolems for every case, but a neatly packed existential
[vpm] pack types of if branches before lubbing

this way we don't end up with fresh, incompatible, skolems for every branch, but a neatly packed existential
you get much nicer lubs this way -- threw in a fast path (I hope) that avoids lubbing when unnecessary (same types)

since lub isn't robust enough to deal with the result of packedType,
and we only really need the trivial case (S =:= T), special case it for now

... don't pack in ifs after typer, also only when virtPatmat
Prepared actors hierarchy for migration.

Internal nodes added so methods relevant to akka can be overridden.

Review by: @phaller
Merge remote-tracking branches 'vjovanov/duration-cleanup', 'adriaanm/topic/virtpatmat' and 'vjovanov/actor-hierarchy' into develop
Revert irrefutability commits.

Temporary reversion of irrefutability commits in interests
of stable milestone.  Expect to restore shortly.
Tweak to string coloring.

Concluded String->String would be more useful more often.
Lots of tedious warning and tree printing work.

Fewer deprecation warnings, prettier trees, prettier
symbols, more polished error messages.

Oh the interesting people you meet handling warnings, I
feel sorry for you all that I get to do it all the time.
One of the characters I met invited me into the "Dead Code
Society" and that's what I'm doing on Tuesdays now.  No of
course you haven't, it's a SECRET society.
Fix for stability failure.

Pattern matcher! Totally unrelated to irrefutability, the pattern matcher
at some point stopped sorting its lookup switch cases, and the butterfly's
wings flapped enough to swap two cases.  Now they're sorted in ascending
order like they're supposed to be.
Restore irrefutability commits.

This reverts commit d8ba5d091e5641553b438ef9930a6023a2709dcd.
Overhauling mixin.

Feel the bugs falling away.
Allows now private primary constructors in value classes.
Merge branch 'master' into feature/pc-execution-contexts