Add sanity testing program
test/sanity: Remove exec <prog> log message
Makefile: Add run-sanity target

Will use this target to run all sanity tests. Depends on all
test programs as it should, and will, run them check for any
error codes.
psi.h: Include errno header
psi.h: Include sys/stat.h header
psi_file: Add _psi_isdir private method

Use this to verify a file to be loaded is not a directory or symlink
psi_file: psi_load checks if path is a directory
Merge branch 'sanity-test-suite'