add support for variables to Script Data input methods

[ehall]

Since this doesn't work, please add support for it.

Variables defined therein should be appended to the very end of <script_path> from the script XML, after all of the index/query/get parameters.

[ehall]

Actually the best thing would be to make this stuff available as system environment variables within the process that is spawned by the poller. Then it wouldn't matter where they appeared on the command line.