put all options into one document

[compn]

ffmpeg has many options and some can be found in man ffmpeg
some can be found at  http://www.ffmpeg.org/ffmpeg.html
and format or codec options can be found only in ffmpeg -formats or ffmpeg -codecs

we need a single document that combines ffmpeg -formats and ffmpeg -codecs and man ffmpeg and all the other docs so it can be easily grepped by people who dont know which document they need.

[saste]

Should be fixed in:

commit 9b4d9d8795b02688b7140b82d716b3885284efc1
Author: Stefano Sabatini <stefasab@gmail.com>
Date:   Tue Mar 19 20:54:26 2013 +0100

    doc: enable compilation of -all tool pages
    
    In particular, add documentation configuration system, through the
    doc/config.texi file.
    
    Fix trac issue #2374.