Use Retrolambda
Use lambda expressions
Do not require thread-safety annotations on anonymous classes
It's faster to not fork the compiler; we just must run Maven with Java 8

Build times:
Java7, no-fork: 60s
Retrolambda, fork: 100s
Retrolambda, no-fork: 80s
Upgraded to Retrolambda 1.1.0
TODO notes
Merge branch 'lambda'