let all be default make command

Makefile

 R_VERSION=3.3.2
 BUILD_DATE=2016-11-08
 
+all: 
+	make sync r-ver rstudio tidyverse verse
+
 r-ver: .PHONY 
 	make -C r-ver/ latest
 rstudio: .PHONY 
@@ -10,9 +13,6 @@ tidyverse: .PHONY
 verse: .PHONY 
 	docker build -t rocker/verse:${R_VERSION} verse/${R_VERSION}
 
-all: 
-	make sync r-ver rstudio tidyverse verse
-
 sync:
 	make -C r-ver/ dockerfiles
 	cp rstudio/Dockerfile rstudio/${R_VERSION}/Dockerfile
@@ -23,3 +23,4 @@ sync:
 
 .PHONY:
 	echo "Building Rocker versioned images locally...\n"
+