When PLAY2_HOME is using a homebrew play 2 installation, you get:
[INFO] --- play2-maven-plugin:1.2.0-SNAPSHOT:compile (default-compile) @ play2-authenticitytoken-sample ---
/usr/local/Cellar/play/2.0/libexec/play: line 51: /usr/local/Cellar/play/2.0/libexec//usr/local/Cellar/play/2.0/
libexec/../libexec/framework/build: No such file or directory
When PLAY2_HOME is using a homebrew play 2 installation, you get: