Squash docker layers to make the scope image fetch nicer.

Makefile

@@ -1,8 +1,8 @@
-.PHONY: all static clean
+.PHONY: all deps static clean
 
 # If you can use Docker without being root, you can `make SUDO= <target>`
 SUDO=sudo
-
+DOCKER_SQUASH=$(shell which docker-squash)
 DOCKERHUB_USER=weaveworks
 APP_EXE=app/app
 PROBE_EXE=probe/probe
@@ -10,14 +10,14 @@ FIXPROBE_EXE=experimental/fixprobe/fixprobe
 SCOPE_IMAGE=$(DOCKERHUB_USER)/scope
 SCOPE_EXPORT=scope.tar
 SCOPE_UI_BUILD_EXPORT=scope_ui_build.tar
-SCOPE_UI_BUILD_IMAGE=weave/scope-ui-build
+SCOPE_UI_BUILD_IMAGE=$(DOCKERHUB_USER)/scope-ui-build
 
 all: $(SCOPE_EXPORT)
 
 $(SCOPE_EXPORT):  $(APP_EXE) $(PROBE_EXE) docker/*
 	cp $(APP_EXE) $(PROBE_EXE) docker/
 	$(SUDO) docker build -t $(SCOPE_IMAGE) docker/
-	$(SUDO) docker save $(SCOPE_IMAGE):latest > $@
+	$(SUDO) docker save $(SCOPE_IMAGE):latest | $(SUDO) $(DOCKER_SQUASH) -t $(SCOPE_IMAGE) | tee $@ | $(SUDO) docker load
 
 $(APP_EXE): app/*.go report/*.go xfer/*.go
 
@@ -30,16 +30,23 @@ $(APP_EXE) $(PROBE_EXE):
 static: client/dist/scripts/bundle.js
 	esc -o app/static.go -prefix client/dist client/dist
 
-$(SCOPE_UI_BUILD_EXPORT): client/Dockerfile client/gulpfile.js client/package.json
-	docker build -t $(SCOPE_UI_BUILD_IMAGE) client
-	docker save $(SCOPE_UI_BUILD_IMAGE):latest > $@
-
 client/dist/scripts/bundle.js: client/app/scripts/*
 	mkdir -p client/dist
 	docker run -ti -v $(shell pwd)/client/app:/home/weave/app \
 		-v $(shell pwd)/client/dist:/home/weave/dist \
 		$(SCOPE_UI_BUILD_IMAGE)
 
+$(SCOPE_UI_BUILD_EXPORT): client/Dockerfile client/gulpfile.js client/package.json
+	docker build -t $(SCOPE_UI_BUILD_IMAGE) client
+	docker save $(SCOPE_UI_BUILD_IMAGE):latest > $@
+
 clean:
 	go clean ./...
 	rm -rf $(SCOPE_EXPORT) $(SCOPE_UI_BUILD_EXPORT) client/dist
+
+deps:
+	go get github.com/jwilder/docker-squash \
+		github.com/golang/lint/golint \
+		github.com/fzipp/gocyclo \
+		github.com/mattn/goveralls \
+		github.com/mjibson/esc