good progress on `save version skew` menu item

- git->diff menu item shows outstanding changes in sandbox
- skew diff and skew save menu items implemented
- git reset command implemented
- git merge tool tweaked a bit to break out 'nothing to merge' test
  and to allow project tool to supply complete/abort block to merge
  tool
tweak project list menu
make .gitattribute persistent
skrewing around with skew

- diff (cached) menu item
  - git diff tool now has options for --cached and (not) --cached
- use loadProject (not revertProject) as final step in skew save
- redecorated project list menu
`skew save` complete

- automatic merge success and failure branches covered ..
dirty packages and repositories added to project list menu
implement `merge` menu item item for project list