Use default Java.

R2 overrides to 1.6, we don't want that.
Explicitly use Java 1.7.

R2 overrides to 1.6, we don't want that.
Explicitly use Java 1.7.

R2 overrides to 1.6, we don't want that.
Oops, not good bash that
Merge pull request #2664 from guardian/tc-jvm-settings

Tc jvm settings
Merge branch 'master' of github.com:guardian/frontend into sbt-typo-fi

Conflicts:
	sbt-tc