Add some more test for verify_hostname.
Updates CHANGES frm 0.13.3 branch.
docs: Update Committer Guide chapter.
Issue LIBCLOUD-485: Added a new constant dictionary,
RESOURCE_EXTRA_ATTRIBUTES_MAP, at the top of the driver which will be used to
store the xpath and transform defintions for each element of the extra
dictionary for each resource. This functionality previously existed in the
private _to_XXXX methods, but was re-located for readibility and to make it
centralize the functionality for easier management and updates going forward.

Signed-off-by: Tomaz Muraus <tomaz@apache.org>