This adds initial support for an sqlite database that is shared across
multiple tasks of a single SBY file and that can track the status of
individual properties.
The amount of information tracked in the database is currently quite
minimal and depends on the engine and options used. This can be
incrementally extended in the future.
The ways in which the information in the database can be queries is even
more limited for this initial version, consisting of a single '--status'
option which lists all properties and their status.
* Rename and move sbysrc/demo[123].sby to docs/examples/demos
* Make them use multiple tasks for multiple engines
* Scan docs/examples for sby files for make test
* `make ci` is now `NOSKIP` by default
* Skip scripts using `verific` w/o yosys verific support
* This does not fail even with NOSKIP set
Organize tests into subdirectories and use a new makefile that scans
.sby files and allows selecting tests by mode, engine, solver and/or
subdirectory. Automatically skips tests that use engines/solvers that
are not found in the PATH.
See `cd tests; make help` for a description of supported make targets.
