corrected issues when loading new files and with new

when a new file was loaded or new was selected, the lines previously in
the document were not reported as being deleted and upon new, the last
line 'empty' remaining was not reported as deleted, but this should not
be reported if all the characters and lines in the document are deleted

a number of additional checks were added to the document changed routine
to catch all of these situations, including not setting the remaining
line 0 as modified when new is selected

also corrected a problem when loading an empty file over an existing
non-empty where the window modified flag was still set

the focus policy of the list view widget in the program view dock
widget was set to no focus so that it does not grab the focus from the
edit box