Add a preferences menu and a settings file.

Signed-off-by: Jim Klo <jim.klo@sri.com>
Read command_path from settings and add it to current PATH environment variable.

Signed-off-by: Jim Klo <jim.klo@sri.com>
Merge pull request #49 from jimklo/path-fix

Expose Settings file in the Menu and Allow configuration of ST PATH to include user configurable locations.