Add omitted copyright headers, update to 2015

[retronym]

I used sbt-header to to the gruntwork. I am considering adding
this to the standard build definition. In the meantime, here's
how to use it locally.

% tail -2 .git/info/exclude
project/local.sbt
/local.sbt

% tail local.sbt project/local.sbt
==> local.sbt <==
import de.heikoseeberger.sbtheader.HeaderPattern

headers := Seq("scala", "java").map(f => (f, (HeaderPattern.cStyleBlockComment, """/*
 * Copyright (C) 2012-2015 Typesafe Inc. <http://www.typesafe.com>
 */
"""))).toMap

HeaderPlugin.settingsFor(Test)

==> project/local.sbt <==
addSbtPlugin("de.heikoseeberger" % "sbt-header" % "1.5.0")

%  sbt createHeaders test:createHeaders
Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=384m; support was removed in 8.0
[info] Loading global plugins from /Users/jason/.sbt/0.13/plugins
[info] Loading project definition from /Users/jason/code/scala-java8-compat/project/project
[info] Loading project definition from /Users/jason/code/scala-java8-compat/project
[info] Set current project to scala-java8-compat (in build file:/Users/jason/code/scala-java8-compat/)
[info] Headers created for 7 files:
[info]   /Users/jason/code/scala-java8-compat/src/main/scala/scala/compat/java8/FutureConverters.scala
[info]   /Users/jason/code/scala-java8-compat/src/main/scala/scala/compat/java8/OptionConverters.scala
[info]   /Users/jason/code/scala-java8-compat/src/main/scala/scala/compat/java8/PrimitiveIteratorConversions.scala
[info]   /Users/jason/code/scala-java8-compat/src/main/scala/scala/concurrent/java8/FutureConvertersImpl.scala
[info]   /Users/jason/code/scala-java8-compat/src/main/java/scala/compat/java8/wrappers/IteratorPrimitiveDoubleWrapper.java
[info]   /Users/jason/code/scala-java8-compat/src/main/java/scala/compat/java8/wrappers/IteratorPrimitiveIntWrapper.java
[info]   /Users/jason/code/scala-java8-compat/src/main/java/scala/compat/java8/wrappers/IteratorPrimitiveLongWrapper.java
[success] Total time: 0 s, completed 04/05/2015 1:57:41 PM
[info] Headers created for 7 files:
[info]   /Users/jason/code/scala-java8-compat/src/test/java/scala/compat/java8/OptionConvertersTest.scala
[info]   /Users/jason/code/scala-java8-compat/src/test/java/scala/compat/java8/SpecializedTest.scala
[info]   /Users/jason/code/scala-java8-compat/src/test/java/scala/compat/java8/BoxingTest.java
[info]   /Users/jason/code/scala-java8-compat/src/test/java/scala/compat/java8/FutureConvertersTest.java
[info]   /Users/jason/code/scala-java8-compat/src/test/java/scala/compat/java8/LambdaTest.java
[info]   /Users/jason/code/scala-java8-compat/src/test/java/scala/compat/java8/SpecializedFactoryTest.java
[info]   /Users/jason/code/scala-java8-compat/src/test/java/scala/compat/java8/SpecializedTestSupport.java
[success] Total time: 0 s, completed 04/05/2015 1:57:41 PM

[retronym]

/cc @Ichoran

[retronym]

It occurs to me now that I should have updated the existing ones to 2014-2015. sbt-header doesn't have a facility to help out here, would be really nice if we can extend it to support this. (I'm thinking about a solution for all the scala/* repos here, not just scala-java8-compat...)