> Note that there may be a merge conflict when you run "git merge stable."
There is a git command, 'git mergetool'. This will go through all conflicting files and launch an external tool (you can configure which) to handle the merge. If you save your merged results, it will git add for you, just leaving you to commit at the end.
(From the manpage) It has support for: kdiff3, tkdiff, meld, xxdiff, emerge, vimdiff, gvimdiff, ecmerge, and opendiff
Editing conflicted files by hand does work, but for complex conflicts I prefer the approach above.