Allow tuples in input terms with the [tuples_to_lists] option

[brigadier]

Allow encoding terms containing tuples with the [tuples_to_lists] option of the encode function. Tuples are encoded as lists. No exception is made for the [{}] and [{k, v}, ...] special cases, and in the current implementation DateTime objects are also encoded as lists.

The rationale for this pull is that in newer erlang projects structures represeting key -> value pairs generally move from proplists to maps, encode and decode functions are not invertible anyway, and transforming manually each and every tuple to list manually before encoding is a tedious job.

Without this option it is fully compatible with previous versions.

I can also add conversion of one-tuple and two-tuple to timestamps, but not sure if this should be default behaviour or a configurable with another paremeter(s) one.

[brigadier]

I'd add that this pull is not ready for getting accepted yet until I add support for datetimes and some tests. It's here for discussing about whether should it be accepted or not.

[paulo-ferraz-oliveira]

You can convert this to a draft if you think it better signals your intention.