build: work around missing readlink -f on Mac

Change-Id: I5d56366cf33a2b02f1886c87815d00cff279779d
Add in roomservice

This is a new implementation of roomservice
use the new github search api to reduce the memory footprint, and make it less processor intensive
allow for unofficial devices to fetch dependencies. just specify your github organization

Change-Id: I3d7a8d46d3effbb3d2480c136c9b6b6e610b9b2e
Support fetching dependencies even if device tree fails.

This is required when device tree depends on dependencies to lunch.

Change-Id: If62cd9777caf768f8070570ca0835052645c6b20
roomservice: Fix os.path.isdir calls

Apparently on some Python installations
it throws exception instead of returning False.

Change-Id: I9d901e3260bab411cf3466346c421594f0922562