refuse to run bitmask/bitmaskd if running as root
in previous releases of bitmask, we were aborting execution of the client if run by root. the reason is that we want to avoid users running bitmask with sudo, since it will mess with the settings by changing permissions of all the files that bitmaskd writes.
however, as a workaround for !113 (merged) I'm precisely relying on bitmask to be run as root for e2e tests. I think we need to capture this particular usage with some kind of flag (BITMASK_AS_ROOT or something like that).