Release version 2.0

Region domain without ghosting

This was a version of the region domain without having ghost
variables.  The domain was able to keep track only of one thing about
references (their addresses) which is useful to keep track of
nullity. This version was used for the VSTTE 2021 submission

Deprecated implementation of octagons in SNF

Deprecated implementation of boxes using MDDs

first stable version used by crab-llvm

Some tweaks to allow using array-graph domain from crab-llvm. It can …

…only be used with crab-llvm branch array_graph. This branch should be removed at some point. Kept for now just in case.

Crab version used in the experimental evaluation of the paper Abstrac…

…t domain of uninterpreted functions published in VMCAI 2016.

Crab version used in the experimental evaluation of the paper Exploit…

…ing Sparsity in Difference-Bound Matrices published in SAS 2016.

Crab version similar to tag-sas16 but using the class mut_val_ref to …

…encapsulate references to graph weights