those are dangerous and can hide real exceptions

basestring, range, long, url*, parse*, unicode, html_unescape
also, remove some obsolete sys.version checks

Python 3.4 added new Enum types that enforce a value belonging to the
enumeration.
This commit retires our homemade enum and use Python's Enum type.
Python 2 compatibility is achieved with "enum34" package.

Housing and Calendar capabilities are updated to use those new enums.

test to handle this case

hydrargyrum authored Jan 24, 2017 and Romain Bignon committed Jan 25, 2017

Since Python 2.7 is the minimum version supported,
collections.OrderedDict is guaranteed to exist and there is no need to
reimplement it.

Signed-off-by: François Revol <revol@free.fr>