patman: Add support for settings in .patman

This patch adds support for a [settings] section in the .patman file.
In this section you can add settings that will affect the default
values for command-line options.

Support is added in a generic way such that any setting can be updated
by just referring to the "dest" of the option that is passed to the
option parser.  At the moment options that would make sense to put in
settings are "ignore_errors", "process_tags", and "verbose".  You
could override them like:

 [settings]
 ignore_errors: True
 process_tags: False
 verbose: True

The settings functionality is also used in a future change which adds
support for per-project settings.

Signed-off-by: Doug Anderson <dianders@chromium.org>
diff --git a/tools/patman/patman.py b/tools/patman/patman.py
index 4181d80..b327c67 100755
--- a/tools/patman/patman.py
+++ b/tools/patman/patman.py
@@ -34,6 +34,7 @@
 import command
 import gitutil
 import patchstream
+import settings
 import terminal
 import test
 
@@ -64,6 +65,8 @@
 Create patches from commits in a branch, check them and email them as
 specified by tags you place in the commits. Use -n to """
 
+
+settings.Setup(parser, '')
 (options, args) = parser.parse_args()
 
 # Run our meagre tests