fixed sloppy overlay arrow behavior:

- The overlay arrow didn't go away when *cscope* buffer was killed

- When the *cscope* buffer was buried the arrow did go away, but the code would
  then try to move the non-existent marker if the user went back to the buffer
At the end of the buffer a result-bound is still respected

This makes killing results work from eob
C-c s [npNP] motion is now restricted to the current result set

This is done for blind navigation. If the user isn't looking at the *cscope*
buffer, they shouldn't be jumping between results.
The same error is now reported when seeking out-of-bounds for all 3 types of motion
using (forward-line -1) instead of (previous-line) in my non-interactive code
comment
separator search after cscope run is now strict
rerun-search now restored the cscope-directory correctly
removed unused code that moves the point in response to process output