Merge PR #2744: Fix Makefile targets dependencies

* Fix Makefile targets dependencies
* Remove unnecessary build deps from install targets
* Create a rule for each tool
* Don't dep test_lint on tools

Makefile

@@ -8,6 +8,7 @@ GOTOOLS = \
 	github.com/golang/dep/cmd/dep \
 	github.com/alecthomas/gometalinter \
 	github.com/rakyll/statik
+GOBIN ?= $(GOPATH)/bin
 all: get_tools get_vendor_deps install install_examples install_cosmos-sdk-cli test_lint test
 
 ########################################
@@ -113,26 +114,29 @@ update_dev_tools:
 	$(GOPATH)/src/github.com/alecthomas/gometalinter/scripts/install.sh -b $(GOBIN)
 	go get -u github.com/tendermint/lint/golint
 
-get_tools:
+get_tools: $(GOBIN)/dep $(GOBIN)/gometalinter $(GOBIN)/statik
 	@echo "--> Installing tools"
 	$(MAKE) -C scripts get_tools
 
-get_dev_tools:
+$(GOBIN)/%:
+	$(MAKE) -C scripts $(subst $(GOBIN)/,,$(@))
+
+get_dev_tools: get_tools
 	@echo "--> Downloading linters (this may take awhile)"
 	$(GOPATH)/src/github.com/alecthomas/gometalinter/scripts/install.sh -b $(GOBIN)
 	go get github.com/tendermint/lint/golint
 
-get_vendor_deps:
+get_vendor_deps: get_tools
 	@echo "--> Generating vendor directory via dep ensure"
 	@rm -rf .vendor-new
 	@dep ensure -v -vendor-only
 
-update_vendor_deps:
+update_vendor_deps: get_tools
 	@echo "--> Running dep ensure"
 	@rm -rf .vendor-new
 	@dep ensure -v
 
-draw_deps:
+draw_deps: get_tools
 	@# requires brew install graphviz or apt-get install graphviz
 	go get github.com/RobotsAndPencils/goviz
 	@goviz -i github.com/cosmos/cosmos-sdk/cmd/gaia/cmd/gaiad -d 2 | dot -Tpng -o dependency-graph.png
@@ -261,7 +265,7 @@ localnet-stop:
 # unless there is a reason not to.
 # https://www.gnu.org/software/make/manual/html_node/Phony-Targets.html
 .PHONY: build build_cosmos-sdk-cli build_examples install install_examples install_cosmos-sdk-cli install_debug dist \
-check_tools check_dev_tools get_tools get_dev_tools get_vendor_deps draw_deps test test_cli test_unit \
+check_tools check_dev_tools get_dev_tools get_vendor_deps draw_deps test test_cli test_unit \
 test_cover test_lint benchmark devdoc_init devdoc devdoc_save devdoc_update \
 build-linux build-docker-gaiadnode localnet-start localnet-stop \
 format check-ledger test_sim_gaia_nondeterminism test_sim_modules test_sim_gaia_fast \