Generate OSGi manifests using bundlor-plugin

- Apply custom-built Gradle 'bundlor' plugin

   This plugin wraps the existing bundlor ant task. Sources available
   at https://github.com/SpringSource/gradle-plugins.

 - Use existing template.mf files

   The bundlor plugin allows for 'inlining' bundlor templates directly
   within build.gradle using the 'importTemplate' property, but opting
   for now to keep the template.mf files separate.

 - Exclude spring-aspects from bundlor processing

   It appears that the bundlor plugin somehow interferes with iajc
   compilation of aspects, resulting in compiler errors. Bundlor
   has been disabled for this project for the time being.

 - Fail the build on any bundlor warning

   The gradle bundlor plugin defaults to failing the build if there are
   any warnings when processing template.mf files. This helps to ensure
   that template.mf files don't drift too far from actual dependency
   declarations. This behavior can be modified by setting

      bundlor {
          failOnWarnings = false
      }

   in the build script.

org.springframework.context/template.mf

@@ -4,7 +4,7 @@ Bundle-Vendor: SpringSource
 Bundle-ManifestVersion: 2
 Import-Package: 
  javax.persistence;version="[1.0.0, 3.0.0)";resolution:=optional,
- org.springframework.orm.jpa.support;version="${spring.osgi.range.nq}";resolution:=optional,
+ org.springframework.orm.jpa.support;version=${spring.osgi.range};resolution:=optional,
  com.ibm.websphere.management;version="0";resolution:=optional
 Import-Template: 
  bsh.*;version="[2.0.0.b4, 3.0.0)";resolution:=optional,