Merge pull request #8 from csmith/master

Tell gradle to use 1.8.

build.gradle

@@ -21,8 +21,8 @@ sourceSets {
     }
 }
 
-sourceCompatibility = 1.7
-targetCompatibility = 1.7
+sourceCompatibility = 1.8
+targetCompatibility = 1.8
 
 repositories.mavenCentral()