Whitespace fix on staging/unstaging all files.

`yes-or-no-p` requires a trailing space on the string passed in,
otherwise you end up with "Stage all changes?(yes or no)".
Merge pull request #1156 from Wilfred/master

Whitespace fix on staging/unstaging all files.
magit-log-format-reflog: better align

Take the length of "rebase -i finish" into account when aligning.
magit-status-show-sequence-help: new option

Most of us know how to continue a rebase or finish a conflicting merge,
so we don't need to be constantly reminded.  But for beginners that is
not so.
magit.texi: use @uref for urls

Also add a @magit macro for extra convenience.
magit-show-diffstat: fix doc-string typo
set :package-version for custom options

For the appropriate custom options set the `:package-version' keyword,
using "2.0.0" as the version.  Replace some occurrences of the "1.3.0"
version; there never was such a release, and that won't change.

Always make `:package-version' the first keyword.
consistently order keywords in `defcustom's

The order is
`:package-version'
`:prefix'
`:set-after'
`:set'
`:type'.