Makefile: `all' is the default target now

This ensures that `magit-version.el' is generated.
Makefile: `lisp' now depends on `magit-version.el'
Remove info manual portions from Makefile
magit-post-command-adjust-point: only use get-pos-property if fboundp
magit-diff-hunk-region-header: bugfix
support stashing when there are conflicts

When a stash is created when there are conflicts then create a fake
index commit whose tree is equal to that of HEAD and create a worktree
commit which contains the conflict marker.

It's not recommended to create such stashes, but we automatically do
create such stashes when the backup mode is turned on - commits with
conflict markers are better than losing information.
Fix some typos in the CONTRIBUTING document
Merge pull request #1672 from RadicalZephyr/master

Fix some typos in the CONTRIBUTING document
Merge branch 'master' into next