OPENDJ-1074 (CR-4030) Implement combined add/del rate tool
Adding an add/del rate tool named addrate.
-opendj-core
    ** EntryGenerator.java:
    * Changing the subtemplate parsing behavior, add the "generated branches" options
    ** TemplateFile.java
    * Adding the "generated branches" options
    ** addrate.template
    * New template used to generate entries

-opendj-ldap-toolkit
    ** addrate (bat and bin)
    * Adding new tool scripts for unix and windows
    ** AddRate.java
    * addrate tool new class
    ** PerformanceRunner.java
    * Using parameter object in constructor, adding some messages localization
    ** PerformanceRunnerOptions.java
    * Helps to simplify the way to initialize a PerformanceRunner instance
    ** MakeLDIF.java
    * Little refactoring in order to allow the addrate tool to use some make-ldif parameters
    ** tools.properties
    * Adding addrate tool message and also some new generic messages
    ** Minor changes (constructor) in other tools and tests files