Fix python 3.2 incompatibility
Keep order of roots

Signed-off-by: Mikhail Gusarov <dottedmag@dottedmag.net>
Add test to check that roots order is preserved

Signed-off-by: Mikhail Gusarov <dottedmag@dottedmag.net>
Start ZIP container (mimetype, root checks)

Signed-off-by: Mikhail Gusarov <dottedmag@dottedmag.net>
Simplify condition

Signed-off-by: Mikhail Gusarov <dottedmag@dottedmag.net>
Remove enum34 dependency: Enum is not used

Signed-off-by: Mikhail Gusarov <dottedmag@dottedmag.net>