- It can be shared for subproject, project and language.
- Much faster as it fetches just once from database instead of fetching
  every value separately

Currently translated at 56.9% (448 of 788)

Currently translated at 100.0% (16 of 16)

- no more extra if
- move select_related to template

Using select_related on last changes and project listing allows us to
fetch more data at once, leading to less database connections and faster
page loading times.

This is cleaner solution than introducing own attributes.

Currently translated at 56.2% (443 of 788)

Currently translated at 67.0% (528 of 788)

We might be more clever on this and do the cleanup conditionally, but
for now this is safe solution as the checks might become stale.

This completes fix for issue #233

When we delete checks for (now) a fuzzy message, the cache needs to be
invalidated.

This might be source of issue #233.

We need this value too often, so using cache here is not optimal - it is
better to always have up to date value calculated.

This will also allow nice progress bars above translation level in future
(issue #196).

Currently translated at 100.0% (788 of 788)