Move all book-related images under "img"

Also:
 * use the "absolute path" syntax as used in the rest
of the image locations
 * png files are no longer required since we use svg for
   the web version and convert to PDF for the PDF version
A referenced file no longer exist --> commented out.
Move all purely website related images under "images"

Also corrected all references.

 * `favicon.ico` existed multiple times -> use the one under images
   (also corrected path in the `conf.py`)
 * also moved `white_wall_hash.png` although this is not
   referenced anywhere and might just as well be removed completely.
Make sure the build dir exists before copying something there.
Forgot to update one image reference.
Adds some PDF metadata. Might get tweaked still.
Please don't tease the PDF version readers :-)
Merge pull request #204 from dietmarw/cleanUpImageLocations

Clean up image locations
Merge pull request #203 from dietmarw/removeTeaser

Please don't tease the PDF version readers :-)
Fix minor typo
Modified Makefile so that the S3 bucket (and path within that bucket) can be specified

The syntax is to run make with S3BUCKET=... on the command line.  Of course, you need to
have the proper credentials to write to the bucket as well.  I added this in preparation
for having an automated way for forks to publish their own versions of the book
automatically to a 'devs' site.
Fixed some theme resources so they used relative paths
Added web site targets for all languages
Switching things to use Docker hub
Added commands to build book
Looking good, but still testing
first batch of translation

Files translated with a basic cross-check.
Probably some syntax issues (we will see after generation of the html).
Need a full review on the html files (both for chinese text and
formatting)
Working through compilation issues with non-English languages
Updates to Chinese .po files
Making sure .po files are all up to date with current text