Bump to 1.2.0

Bump to 1.0.4

Bump to 1.0.3 / fix dialyzer warnings

Bump to 1.0.2

Bumping to 1.0.1 given important bugfix

1.0.0: adding linking between POBox and owner

This is to respect safer process-like semantics, and can be undone
on demand by the box owner manually unlinking the process.

See README.md for details.

Using Size when dropping items

POBox tracks the size of all the entries it has for quick matching to
know when a buffer is full or not. However, it does *not* make use of
that data when dropping more than 1 element (either in drop or
push_drop) and instead recalculates the buffer size dynamically (O(n)).

This behaviour can make it so busy buffers that need to drop data
continuously because they're full end up doing a lot more work than
nearly-empty buffers, which is counter-productive (they should all be
doing nearly no work at all).

This patch makes it so that the size is explicitly passed to the drop
functions of the module, bringing that length check to a no-cost
operation.

Adding `keep_old` buffer type.

Keep Old buffer type acts like a queue that accumulates old
messages and denies newer ones when full.

Documentation also got updated to reflect the change.

initial commit