* Makefile: new target install-using-eui (will be used in Debian
  package building), refactored makefile code into
  do--symlink-bbbikeexe
* moved debian build stuff into old-debian directory
* new debian build stuff
* new 48x48 transparent version of bbbike logo

  Created using

    inkscape -f images/srtbike_logo.svg --export-png=/tmp/srtbike38a.png --export-area-page -w 38 -h 38
    convert -bordercolor none -border 5x5 /tmp/srtbike38a.png images/srtbike48a.png
* fixed Makefile targets for debian install
  * use REAL_BBBIKE_DEST_DIR
  * check for /etc/debian_version, too
* install-freedesktop Makefile target
* update MANIFEST for new desktop/icon stuff
* data update (minor)