This breaks ABI.

crakoon releases should not break API or ABI in a backwards-incompatible way. The latter implies when a binary is compiled/linked against a certain version of the library, it should still work as expected even when a newer/later version is used at runtime.

C enum values are integrals whose value is determined by the compiler based on their occurrence in the enumeration (or any defined value). As such, this change would break ABI: whenever some code is compiled against crakoon 1.1.X and uses ARAKOON_SEQUENCE_ITEM_ASSERT, this would use '3' (or '2', don't know the base offset by heart) internally. When we run this binary against crakoon 1.2 (or whichever version this change goes in), this would all of a sudden be interpreted as being ARAKOON_SEQUENCE_ITEM_TYPE_ASSERT_EXISTS, which is obviously not the intention.

As such, enums should be extended at the end, so all existing enumeration values retain their correct identifier.