Add spring-build 2.2.3.

spring-build was previously included via an svn:external. Adding
directly to the source tree under Git to avoid the need for a git
submodule.

In order to build from any earlier commit, it is recommended to
export spring-build or symlink an existing copy into the root
of the spring-framework project and then build normally.

$ svn export https://src.springsource.org/svn/spring-build/tags/project-build-2.2.3 spring-build

spring-build/scripts/create

@@ -0,0 +1,10 @@
+#!/usr/bin/env ruby -wKU
+$LOAD_PATH << File.expand_path(File.dirname(__FILE__))
+require "rubygems"
+require "choice"
+require "project-gen/options"
+require "project-gen/creator"
+
+
+Creator.create(Choice.choices)
+