magit-dispatch-popup: Use magit-show-refs-popup
magit-dispatch-popup: Use magit-process

magit-dispatch-popup wasn't updated when magit-display-process was
renamed magit-process-display-buffer [1]. Later, the command
magit-process was added and magit-process-display-buffer was turned into
a non-interactive function, so use magit-process for the dispatch popup.

[1] bca9560d763b683a4ef98377448480fd93aa0f87
[2] cff64191fdf3f010b77469673ad299f5019bbf96
Merge pull request #1652 from kyleam/n/update-dispatch

Update magit-dispatch-popup
Clarify steps to install magit/next.
Merge pull request #1661 from mwfogleman/next-readme

Clarify steps to install magit/next.
Makefile: don't use package-initialize

See #1653.
magit-apply: don't always use --3way

With this argument changes are applied to the index in addition to
the working tree, which usually is not desirable.  And if the file
is question modified in the working tree, then it will cause `git
apply' to always fail.

With a prefix argument still use `--3way', but remove the option
`magit-apply-tree-way'.
magit-stash-save: avoid creating an empty "untracked" commit
fix several stashing bugs
magit-stash-create: inhibit commit signing
Merge branch 'n/fix-stash' into next
Merge branch 'n/find-dash' into next