Adding the searchable plugin

Uhh, this was not easy. I had to set $JAVA_HOME to use jdk 1.7 and
IntelliJ to use Java 1.7. Then I had to change DataSource.groovy to use
Hibernate 3 instead of 4. I also had to do the same in
BuildConfig.groovy. Since I’m using grails 2.4.3, the install-plugin
command no longer works.