use `max_int` instead of a hard-coded constant
Added git ignore
Conform Makefile to git
Source code positions, better error reporting, better printing
Commit before we replace current master with something sensible
Source code positions, better error reporting, better printing
Better parser and error reporting.

The parser keeps track of locations now and so errors can be
reported by line number.
Merge branch 'master' into devel. This is part of a cleanup
process so that the experimental unfinished non-working stuff
that was on master can be moved over to a separate branch.