README.md: move "Getting Started" before "Getting Help"
README.md: add "Table of Contents"
README.md: assimilate INSTALL.md

A Table of Contents is better than two files.
README.md: minor improvements
magit.texi: remove FAQ and ChangeLog

Remove the sparse FAQ and the outdated one-entry ChangeLog;
and instead link to the more up-to-date online information.
magit.texi: update information about minimal Emacs and Git
magit.texi: remove outdated "Developing Extentsions" section

That will come back, but not until after the api has stabilized.
magit.texi: recommend against the "rewrite" functionality
magit.texi: improve "Introduction" a bit
magit.texi: thank every contributor; maintainers by name

Thank you guys and gals!
synchronize magit.texi and README.md
Makefile: assimilate AUTHORS.md.in
AUTHORS.md: update list of contributors
AUTHORS.md: also link to contributor list on github
Merge branch 'pr/redoc'
magit-refresh{,-all}: correct doc-string
magit-run*: always mark current buffer for refresh

Previously it was not marked as such when starting an async process.
magit-process-sentinel: refresh all marked buffers

In `magit-process-sentinel' refresh all buffers that were marked as
needing to be refreshed and the status buffer.  Previously only the
command buffer was refreshed.

This fixes several existing bugs and a whole class of bugs nobody
bothered to report yet.
magit-git-command: don't refresh before command is done

Since the last commit the Magit buffers are actually refreshed after
running the command is done.  So stop refreshing "shortly after starting
the process" as we previously did (and which in some case happened to do
the refreshing a the right time, more often not).
magit-section-action: add NOREFRESH argument

Some actions do *not* require a refresh; subsequent commits will use the
new argument in those cases.