Make all paths relative to $EV3SOURCE

Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
All mkdir -p

Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
Use fakeroot for now

Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
All scripts set -e

Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
No apps for now

Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>