Ignore patterns
***************

Ignore patterns need to be flexible but simple.

Based on the system from rsync, which is in turn based on that of
CVS.  However, I won't implement all of this at first but rather add
bits as they seem to be needed.

First build a list by concatenating:

* per-user configuration
* per-tree configuration
* command line options

Just one ``.bzrignore`` at tree root?

File can contain '+ ' and '- ' prefixes to include and exclude things,
also '#' for comments.
 
Should have a ``--ignore`` command line option that specifies ignore
patterns; by putting a ! in this you can turn off any other includes.
(Similar to CVS.)