Feat cronjob (#23)

Make possible to declare cronTabs inside docker-compose file.

⇒ Also, add multiple compose file injection with `-c` arguments 

⇒ Also, fixes “ignore depends on” for same pod 

⇒ Also fixes
 
* fix [Be able to specify compose.yml files and its override #21](https://github.com/metal3d/katenary/issues/21)
* fix [Be able to ignore ports to expose in a katenary.io/ports list #16](https://github.com/metal3d/katenary/issues/16)

And more fixes… (later, we will use branches in a better way, that was a hard, long fix process)

generator/main_test.go

@@ -127,7 +127,7 @@ func setUp(t *testing.T) (string, *compose.Parser) {
 	}
 
 	composefile := filepath.Join(tmpwork, "docker-compose.yaml")
-	p := compose.NewParser(composefile, DOCKER_COMPOSE_YML)
+	p := compose.NewParser([]string{composefile}, DOCKER_COMPOSE_YML)
 
 	// create envfile for "useenvfile" service
 	err = os.Mkdir(filepath.Join(tmpwork, "config"), 0777)