DDlog v0.50.0

[0.50.0] - Oct 20, 2021

Libraries

• internment.dl: optimized the implementation of Intern::default() to avoid
  excessive heap allocations and contention.

API changes

• ddlog_clone(): C and Java API to clone a ddlog_record.

Bug fixes

• Fixed parser bug caused by grammar ambiguity whereby index could be interpreted
  as part of an index declaration or as a regular identifier.