Joblist: change page select widget name to "JobList"

MediaEdit added months spin.  Not sure I like it because 365=yr but 30 days is
not always equal to a month.
JobLog: add Icon for page selector.
mainwin and others.  Move dockPage() into the class' constructors so that the
createPage functions in main win are not of benefit.
Jobs: a new page for displaying jobs and job defaults.