add some actual testing, fix basic typos and bugs.  still more to do, but it's a start.
uncomment tests that should run
one more sync up
fix stuff that was not written by spec:
rewrite writeNull
rewrite writeInt
rewrite writeString
rewrite writeBytes

have writeLong and writeDouble throw errors, since supporting them in node.js
is somewhat painful (lack of [u]int64_t, need to write own encoder for double).