This doesn *not* make access to the class threadsafe though! All
retrieved pointers may still be able to change. This is a bit dangerous,
so ideally any AsContext class should be initialized once and then never
be modified again.
In future, in case people really use this in a multithreaded
environment, it may be useful to add a sealing mechanism to this class.

Resolves: #261 (again)

Currently translated at 100.0% (335 of 335 strings)

Currently translated at 100.0% (335 of 335 strings)

Currently translated at 100.0% (335 of 335 strings)

Resolves: #183

This is a very basic implementation, but it will do the job for now. In
future, exceptions should probably get their own prefix and not share @
with license IDs.

Resolves: #261

Currently translated at 100.0% (335 of 335 strings)

Makes the life of backporters easier. This is the version used by latest
Debian stable (buster) so it's a reasonable target.

Previously the cache created in an AsPool constructor would always get
thrown away immediately when load() was called, which is very common.
Now we try to reuse it and only drop it if actually necessary.

I normally don't care, but the inconsistencies bugged me a bit. After
this, we can go back to updating the dates whenever a change is actually
made.

Some entities only did subpar locale fallbacks. So instead of having
modules roll their own, use the same algorithm everywhere.
Resolves: #262

Currently translated at 8.1% (27 of 333 strings)

The function still had its old name which sounded like you would get the
actual locale with it, which is not the purpose of this function.

Currently translated at 100.0% (333 of 333 strings)

Currently translated at 100.0% (333 of 333 strings)