Add ability to disable projects (#97)

Conflicts:
	pootle/apps/pootle_project/models.py
	pootle/core/decorators.py
TranslationProject: added convenience `disabled()` manager method
translationproject: Add the ability to disable a translation project

Cherry-Picked-From: a6b5dd9db6e6495444730d4e33b354315e86e967
Disabled translation projects aren't to be updated

No log error messages while update_stores after whole directory
of translation project was removed

Cherry-Picked-From: 1ad4f599abe8c870c3793bc7facd95fed031aeb4
Tests: added Arabic language fixture
Tests: allow passing options when creating projects
Tests: added disabled tutorial project
Tests: added disabled TP
Tests: check `get_path_obj()` behavior
Tests: allow having stores with the same name
Fail unit submission if fuzzy flag is set

Unless users have administration privileges, now they're required to clear
the fuzzy flag.

This covers the backend side of evernote/pootle#157.

Conflicts:
	pootle/apps/pootle_store/forms.py
Require non-admin users to always clear the fuzzy flag

Non-admin users now have the fuzzy checkbox disabled by default. It'll be
shown if the initial state of the unit is fuzzy or some other action (MT
translation, auto-translation etc.) turned the unit into fuzzy state.

Whenever the fuzzy checkbox is displayed for non-admins, they are forced
to clear it, otherwise the submit button won't be enabled.

This covers the frontend side of evernote/pootle#157.
Django 1.5: fixed `UnitStateField` behavior

The interpretation of values changed in the templates and the field now is
getting values other than strings as well (`True`, `False` and `None`).

Conflicts:
	tests/forms/unit.py
Partial pick: Arbitrary path support for checks' and overview stats

Pick note: This is a missing bit from the first pick.

Conflicts:
	pootle/apps/pootle_store/views.py
	pootle/apps/pootle_translationproject/urls.py
	pootle/apps/pootle_translationproject/views.py
	pootle/static/js/stats.js
	pootle/templates/editor/_scripts.html
	pootle/templates/translation_projects/overview.html
Followup: Retrieve this from settings

We already picked the commit that did this change, so no idea why it is gone.
New overview page for languages

Pick notes: Had to adjust the changes because we already picked later changes
    and other changes were not necessary.

Conflicts:
	pootle/apps/pootle_language/models.py
	pootle/apps/pootle_language/views.py
	pootle/apps/pootle_misc/browser.py
Partial pick: Clarify the difference between context and resource objects

Pick notes: This is picking the missing bit that we left behind in the first
    picking.

Conflicts:
	docs/developers/glossary.rst
	pootle/apps/pootle_store/views.py
New overview page for projects

Pick notes: Had to adjust the changes because our code was different. In this
    commit we lose tags in project listing.

Conflicts:
	pootle/apps/pootle_misc/browser.py
	pootle/apps/pootle_project/models.py
	pootle/apps/pootle_project/views.py
Partial pick: Simplified item generation

Pick notes: The rest of the changes in the original commit were already
    picked in the past.

Conflicts:
	pootle/apps/pootle_misc/browser.py
Restore project listing page without any bells & whistles

Pick notes: Had to do some adjustments because of code divergence.

Conflicts:
	pootle/apps/pootle_misc/browser.py
	pootle/apps/pootle_project/views.py