Update to Scala 2.12

[ExE-Boss]

This PR upgrades NOVA-Scala to use Scala 2.12.1

New features:

• Scala lambdas and Java 8 lambdas are now binary compatible.

Note that in Scala:

val lambda = variable => variable

is still a type of Function1 unless you do

val lambda: java.util.fuction.Function = variable => variable

in which case it becomes a Java 8 Function.
This isn't a problem in Java 8, as Java 8 has to have the type declared.

• Traits now compile directly to an interface with default methods where possible.

More about Scala 2.12:

http://www.scala-lang.org/news/2.12.0

[RX14]

Is there a reason we shouldn't delete this? We don't need backwards compat because we have no releases.

[ExE-Boss]

There isn't any specific reason as to keeping it, I don't even use it in #4.