BEL proposal BEP-0013: Update annotation handling

[Vasundra Touré]

Hi,

This BEP proposes a way to better handle annotations in BEL script.

First, it updates the syntax for defining annotations in the header of BEL Script and for setting annotations in the body of BEL Script. Second, introduces the CURIE type of annotation in addition to URL, LIST, PATTERN, and MIRIAM. Third, it introduces BEP-0008 OBO-style identifiers for definitions of annotations. Finally, it introduces alternate semantics for the SET Citation annotation that resemble OBO-style identifiers.

Link to PR: https://github.com/belbio/bep/pull/34