New build parameters added to the ANT build

Hello, after using the plugin, I want to congratulate the developer. But I had to go over the code to understand what variables needed to be set and the values that you needed since there was no example.

Additionally, the code had STATIC references to the location where TMP Report where created, and this was not working well in Pentaho 5, therefore I added 2 new ANT variables that are configured in the build.properties so the reports tmp location and the Birt Viewer can be configured.