install: relative symlinks, add mime types and icons, needed empty directories

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@46145 4005530d-fff6-0310-9dd1-cebe43e6787f
install: do not install bat and sh files

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@46146 4005530d-fff6-0310-9dd1-cebe43e6787f