Add note about indentation to README
Fix indentation to 3 spaces (not 2)
Add documentation of `ClientSettings` extension
Remove '.' (period) at end of line on parameters
Add UserManager permission to :auth: field
Change `xml` to `schemaXml` in Session extension
Add `Group/Get` Action
Add :optauth: field to CHAOS domain

For Actions that _may_ require authentication depending on e.g.
parameters.
Change indentation from 2 to 3 spaces
Fix spelling mistake in `MetadataSchema/Create`
Fix v4/v5 `Group/Get` Action
Add `create_group_permission` to :auth: field
Add `Group/Create` action
Change :rtype: to :returns:
Add `Group/Update` and `Group/Delete` actions