Travis: bump Django to 1.6.5 add 1.7.1

Allow Django 1.7.1 to fail as it wants Django migrations and not South
migrations.
Travis: disable migration testing

Bring this back once we have a migration path from older versions.
Travis: force MyISAM

At least until we close #3363 and #3364
Amagama: update URL to the new location.

Conflicts:
	pootle/settings/60-translation.conf
requirements: reminder to drop argparse
setup: install_requires can process --allow-external and --allow-unverified
Logging: add default log directory
requirements: importlib on Py < 2.7