Merge pull request #361 from dagoodma/map_fixes

Map fixes
Created new SLUGS MAV and added nav modes.
 Added SLUGS control widget.
Added navigation mode to top toolbar.
New slugs messages. Hid nav mode on tool bar for non-slugs.
Added updated slugs mavlink messages.
Added passthrough surface and mid-level command functionality.
Added slugs control widget.
Added tabbed slugs view and removed old slugs references.
Styled widget, disabled ISR, and styled nav mode label.
Removed old commented out code.
Enabled ISR button and expanded nav bar label length to fit PASSTHROUGH.
Added HIL functions to slugs mav.
Added HIL support for slugs.