OPENDJ-808 (CR-1439) Implement a simple commons REST based HTTP connection handler

Added support for Ivy from the ant file build.xml.
"Apache Ivy™ is a popular dependency manager focusing on flexibility and simplicity."

As part of the build, Ivy gets downloaded and installed as ext/ivy.jar, if it was not already installed.
Ivy will then download all the dependencies and transitive dependencies from forgerock artifactory, maven central and oracle public maven repo as specified in ivy.xml and ivysettings.xml and put them under the lib/ directory. This step is similar to what maven does.
Finally, I removed je.jar and mail.jar as they also get downloaded by Ivy now.

Ivy uses a download cache under ~/.ivy/cache to prevent always downloading the jars from internet.
I made sure that after a successful build, rebuilding without the network works fine.
I also made sure the built zip contains only thebinary jars, and not sources jars or javadoc jars.

Here is now the content of the lib/ directory in the OpenDJ-2.5.0.zip file:
$ ls build/package/OpenDJ-2.5.0/lib/lib/
activation-1.1.jar
grizzly-framework-2.3-rc6.jar
grizzly-http-2.3-rc6.jar
grizzly-http-server-2.3-rc6.jar
grizzly-http-servlet-2.3-rc6.jar
grizzly-rcm-2.3-rc6.jar
javax.servlet-api-3.1-b05.jar
je-5.0.48.jar
launcher_administrator.exe
mail-1.4.1.jar
opendj_service.exe
winlauncher.exe


Please also have a look at the attached out.patch file since crucible does not allow me to upload it as a patch. It contains changes to SVN properties and removed files.