Add spring-build 2.5.2

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-2.5.2 spring-build

spring-build/docbook/css/html/highlight.css

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2010 SpringSource
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+.hl-keyword {
+  color: #7F0055;
+  font-weight: bold; 
+}
+
+.hl-comment {
+  color: #3F5F5F;
+  font-style: italic;
+}
+
+.hl-multiline-comment {
+  color: #3F5FBF;
+  font-style: italic;
+}
+
+.hl-tag {
+  color: #3F7F7F;
+}
+
+.hl-attribute {
+  color: #7F007F;
+}
+
+.hl-value {
+  color: #2A00FF;
+}
+
+.hl-string {
+  color: #2A00FF;
+}