Adding GLP_ICUTSELECT callback:
- ios_process_cuts marks the cuts as selected after turning the cut into a row.
- This callback happens after ios_process_cuts marks and before the pool is
  cleared by ios_clear_pool.
Cleaning up the git directory to not track autogenerated files.
Branch logging
- Adds to the integer interface a callback function for when branches are made.
  This is called after branch_on.
- Added a public function glp_ios_branch_log.
  This returns the structural variable for the branch as well as the value
  branched on, and the ids of the nodes for the down and up branches.
  If both branches are infeasible, the ids are -1 for both dn and up.
  If one branch is infeasible (and no branch is done), this returns -1 for
  the infeasible branch and the current node id for the up branch.
- Each node now has a unique ordinal associated with it.
- Added a public function to convert the id of an active node to the unique
  node ordinal.
- Added a callback for when a node is closed due to being linearly infeasible.