preauth: fail early if not executed as root
replace split with ld-jsonstream

ld-jsonstream fails early if maxBytes is exceeded, split does not
fail early when maxLength is exceeded and has extra deps.
preauth: add tests
preauth: add test with auth request
preauth test: set encoding utf8 on stderr, stdout
preauth: create world writable socket
preauth: don't debug password
push_request: work with undefined values
auth_request: work with undefined offset
pull_request: support undefined values
oplog_reader: test parsed BSON objects
oplog_reader: test tailable
vcexec: parse incoming oplog BSON stream
vs, vcexec: fix and test initVCs
oplog_reader: exclude offset by default

and add includeOffset option
oplog_reader: debug info
vs test: extend testing of initVCs
snap: check createServer, but should be good