Merge pull request #7 from lbt/hybris-10.1

Clean up /dev mounting and use devtmpfs.
Make an sffe-installer target

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
Helper command for use in inject loop

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
Don't use a fifo for stdout - it blocks commands if a drain is not being used and
isn't needed as all logging is done to /init.log anyway
Clarify docs too

Signed-off-by: David Greaves <david.greaves@jollamobile.com>