Update to next development version, 0.6.0-SNAPSHOT (#303)

Author: fsteeg

build.gradle

@@ -53,7 +53,7 @@ subprojects {
   }
 
   group = 'org.metafacture'
-  version = '0.5.1'
+  version = '0.6.0-SNAPSHOT'
 
   apply plugin: 'checkstyle'
   apply plugin: 'eclipse'