Back-ported actiity sorting fix .
intercepted use of disabled and replaced with disability
Updated UX for disability instead of disabled.
Updated unit tests.
Fixed seo.models and adjusted tests to expect the right thing.
Merge pull request #919 from DirectEmployers/disabled-to-disability

[PD-638] Disabled to disability
Merge pull request #917 from DirectEmployers/activity-sort-fix

[PD-636] Remove duplicates caused by sorting by Activity
Merge branch 'master' of github.com:DirectEmployers/MyJobs into user-groups

Conflicts:
	seo/models.py