pfSense

Support adding to an array in array_set_path()

- Avoid infinite loop with empty paths.
- Support setting $value to the $arr root.
- If $path contains a trailing forward-slash '/', push $value to the
leaf node; replace the leaf node if it's a scalar.

Update .gitignore and remove autosave file from tests

Relocate ConfigLibTest.php to new tests directory

To correctly handle running test in situ, add set_include_path() call to add
relative src/etc/inc path to the include path string