Checkpoint commit for OPENDJ-1075 Port server make-ldif tool to the SDK
CR-2586

Refactor and clean-up of ported code.

* Reduce visibility of classes and methods to private or package 
   private
* Clean up of javadocs, remove useless javadocs
* Refactoring to reduce duplication and simplify code
* EntryGenerator class
 - Support to override of constants with setConstant() method
 - Remove internal Builder
 - Remove the generation thread
* Add more defaults, including default template file and default 
   resource path
* Add tests in EntryGeneratorTestCase
* New test case TemplateTagTestCase
* Add possibility to build RDN object from a list of AVAs
* Port of Pair class from opendj server
* New template people_and_groups.template