pull_request: new verifier of data pull requests
rename data_request to push_request
vcexec: load renamed push_request
new preauth: handle connection first line of JSON
new server2.js: fork preauth and verify auth req

copy config/example.json to config/test.json

start server with sudo ./server2.js

test with something like:
echo '{ "username": "youruser", \\
"password": "yourpass", "database": "test", \\
"collection": "foo" }' | nc -w 5 127.0.0.1 8182
vs: new initVCs and trackOplog2
vs: new _verifyAuthRequest and _handleIncomingAuthReq
preauth: handle initial request to setup sockets
rename preauth.js to preauth_exec.js
preauth: don't use removed authRequest.map
pull_request: accept either path or port and host