- Added `exclude` option - Made ListChanges into a subclass of RetrieveChanges and abstracted out   some of the change detection logic - `exclude` and `include` now use regex - RetrieveChanges will now look for a package.xml in the target path.   If found, it will add any new metadata items from the changes list to the package.xml - Added support for project to configure ignores in the cumulusci.yml   under project -> source -> ignore
- Added `exclude` option
- Made ListChanges into a subclass of RetrieveChanges and abstracted out
  some of the change detection logic
- `exclude` and `include` now use regex
- RetrieveChanges will now look for a package.xml in the target path.
  If found, it will add any new metadata items from the changes list to
the package.xml
- Added support for project to configure ignores in the cumulusci.yml
  under project -> source -> ignore

SalesforceFoundation/CumulusCI,SalesforceFoundation/CumulusCI