BDDCML v2.0
major changes:
- added constraints specified by user - needed to change interface of bddcml_upload_subdomain_data and bddcml_setup_preconditioner
- selection of corners made more robust with respect to disconnected subdomains - each of them separately investigated for continuity
- changed computing of unique tag of MPI messages to avoid large integers and core counts - tested up to 32k cores