Add test for batteries module, update deps

Makefile

@@ -3,6 +3,7 @@
 BUILDOPTS=-ldflags="-s -w" -a -gcflags=all=-l -trimpath
 
 BINARY=i3status-go
+TEST1=battery-test
 
 ## Use calssic targets where first one is deafult target
 all: clean build
@@ -11,10 +12,12 @@ all: clean build
 build:
 	go build ${BUILDOPTS} -o ${BINARY} ./cmd/${BINARY}
 
+battery-test:
+	go build ${BUILDOPTS} -o ${TEST1} ./cmd/${TEST1}
 
 ## Remove binary with golang compiler' means
 clean:
-	rm -rf ${BINARY}
+	rm -rf ${BINARY} ${TEST1}
 
 
 ## Misc target, for development purposes. Updates vendored libs, brutal way.