This scheduler uses a tree-stable-timer like the default one, but uses a separate timer for each branch.
The arguments to this scheduler are:
True if the change is worth building, and
it is not. Unimportant Changes are accumulated until the build is
triggered by an important change. The default value of None means
that all Changes are important.
fileIsImportant: if the change filter filters out a Change, then it is
completely ignored by the scheduler. If a Change is allowed by the change
filter, but is deemed unimportant, then it will not cause builds to start, but
will be remembered and shown in status displays.
branches (deprecated; use change_filter)
categories (deprecated; use change_filter)