Rename build script to avoid conflict with bazel

It's difficult to include this repository using bazel, because
the file named "build" conflicts with new_go_repository generation
on case-insensitive filesystems (ref
https://github.com/bazelbuild/rules_go/issues/234). This change
renames the file to something that doesn't conflict, and also
renames the test script for consistency.

build.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+set -e
+
+ORG_PATH="github.com/containernetworking"
+REPO_PATH="${ORG_PATH}/cni"
+
+if [ ! -h gopath/src/${REPO_PATH} ]; then
+	mkdir -p gopath/src/${ORG_PATH}
+	ln -s ../../../.. gopath/src/${REPO_PATH} || exit 255
+fi
+
+export GO15VENDOREXPERIMENT=1
+export GOPATH=${PWD}/gopath
+
+echo "Building API"
+go build "$@" ${REPO_PATH}/libcni
+
+echo "Building reference CLI"
+go build -o ${PWD}/bin/cnitool "$@" ${REPO_PATH}/cnitool
+
+echo "Building plugins"
+PLUGINS="plugins/meta/* plugins/main/* plugins/ipam/* plugins/test/*"
+for d in $PLUGINS; do
+	if [ -d $d ]; then
+		plugin=$(basename $d)
+		echo "  " $plugin
+		go build -o ${PWD}/bin/$plugin "$@" ${REPO_PATH}/$d
+	fi
+done