add proxy parameters to JobSchedulerCheckUpdates

JobSchedulerCheckUpdates uses HttpClient for the web service request and FTP to download the updates, so possibly two proxies would need to be configured.

For HttpClient, see: http://softwarecarnival.blogspot.com/2008/03/apache-http-client-and-proxy-settings.html
For SOSFTP, see: http://wiki.apache.org/jakarta-commons/Net/FrequentlyAskedQuestions
(perhaps mo can build this into SOSFTP)