README -> README.md

Signed-off-by: Martin Stensgård <mastensg@ping.uio.no>
add BILL_OF_MATERIALS

Signed-off-by: Martin Stensgård <mastensg@ping.uio.no>
.gitignore: ignore /trigger_*

Signed-off-by: Martin Stensgård <mastensg@ping.uio.no>