magit-{svn,stgit,topgit}-mode: cosmetics
magit-insert-svn-{unpulled,unpushed}: fix bitrot
magit-insert-svn-{unpulled,unpushed}: cosmetics
magit-insert-svn-remote-line: append newline
magit-insert-svn-remote-line: add to correct hook
magit-svn-*: properly deal with magit-current-popup-args

`magit-current-popup-args' is like `current-prefix-arg', if possible
it should be consumed inside `interactive' and passed to the body as
a function argument.
magit-svn-remote-update: never silently do nothing

Like for other svn commands to NOT make sure svn has been setup before
running `git svn fetch'.  This way the user gets an error message, which
is better than silently doing nothing.
rename magit-svn-{remote-update => fetch}
magit-svn-enabled: sanitize
magit-svn-get-{url,rev,ref}: new functions

Add new functions `magit-svn-get-url', `magit-svn-get-rev' and
`magit-svn-get-ref'.  `magit-svn-get-ref' actually already existed,
but it used to do what is now done by `magit-svn-get-rev'.  In turn
remove the rather complicated `magit-svn-expand-braces-in-branches',
`magit-svn-get-local-ref', `magit-svn-get-ref-info-cache' (yes there
was a cache), `magit-svn-get-ref-info' and the old implementation of
`magit-svn-get-ref'.  This shrinks the implementation by 4/5, just
saying.
magit-svn-fetch-externals: absorb magit-svn-external-directories
magit-svn-fetch-externals: move definition
magit-svn-fetch-externals: don't run git-svn-fetch directly

Running git-svn-rebase is enough, it also fetches.
rename magit-svn-{find-rev => show-commit}

While this command uses `git svn FIND-REV' to determine the git commit
it then uses `magit-SHOW-COMMIT' to display it in a buffer, and that's
what the name should be based on, because this command is a variant of
the latter.
magit-svn-show-commit: use appropriate readers
magit-insert-svn-remote-line: change how rev is displayed

Prefix the svn revision with "r" because apparently this is how this
is commonly done.  Also display the revision right after the heading
and using face `magit-hash' because that's what we do with Git hashes
too.
rename magit-insert-svn-remote{-line => }

We no longer use this "-line" suffix anywhere else either.
magit-svn-*: add more meaningful doc-strings
magit-svn.el: shorten commentary

Don't mention every command, just the popup.
magit-svn-mode-lighter: default to "Msvn"

instead of "Svn".