scripts/image: compress NOOBS filesystems as tar.xz

Signed-off-by: Stephan Raue <stephan@openelec.tv>
config/noobs: fix partition layout file

Signed-off-by: Stephan Raue <stephan@openelec.tv>
config/noobs: provide png icon

Signed-off-by: Stephan Raue <stephan@openelec.tv>
config/noobs: provide slides

Signed-off-by: Stephan Raue <stephan@openelec.tv>
projects/*/options: reword OS description

Signed-off-by: Stephan Raue <stephan@openelec.tv>
config/noobs: fix partition layout file

Signed-off-by: Stephan Raue <stephan@openelec.tv>
Merge branch 'master' of github.com:OpenELEC/OpenELEC.tv