Provide synchronous SCM polling in the order of dependencies. For now, to
activate, edit hudson.triggers.SCMTrigger.xml and add
<synchronousPolling>true</synchronousPolling>
This change also relaxes visibility of Trigger.run() from protected to
public.
TODO: connect the UI and provide a global crontab spec setting. This will
probably happen when I get some feedback on this change.
git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@4700 71c3de6d-444a-0410-be80-ed276b4c234a