Add a lint script to golint correctly and use it

Makefile

@@ -35,6 +35,7 @@ vendor-update:
 	@echo
 
 verify: check-reqs
+	@./scripts/lint.sh
 	@GO15VENDOREXPERIMENT=1 gometalinter -D gotype -E gofmt --errors --deadline=5m -j 4 $$(GO15VENDOREXPERIMENT=1 glide nv)
 
 test:

scripts/lint.sh

@@ -0,0 +1,16 @@
+#/bin/bash
+
+# NOTE: This script needs be run from the root of the GD2 repository
+
+# Find all Go source files in the repository, that are not vendored or generated
+# and then run golint on them
+
+RETVAL=0
+
+for file in $(find . -path ./vendor -prune -o -type f -name '*.go' -not -name '*.pb.go' -print); do
+  golint -set_exit_status $file
+  if [ $? -eq 1 -a $RETVAL -eq 0 ]; then
+    RETVAL=1
+  fi
+done
+exit $RETVAL