Fix robotstxt.org url

Looks like http://robotstxt.org does not resolve without www.
Remove unnecessary .gitkeeps

Given that there are files already present in these directories the `.gitkeep`s are unnecessary.
Merge pull request #2546 from karlfreeman/clean-up-gitkeeps

Remove unnecessary .gitkeeps
Merge pull request #2545 from karlfreeman/patch-1

Fix robotstxt.org url
[Fixes #2557] nicer error message if someone creates server/index.js and it doesn’t export a function
Merge pull request #2558 from stefanpenner/better-error

[Fixes #2557] nicer error message if someone creates server/index.js and...
because
restart server and trigger LR on server file change
debounce server restart at 100ms when watching server files
use master of broccoli-sane-watcher to enable watchman support
force watchman on for now (until it is auto-detected by
broccoli-sane-watcher or sane)
allow GH deps
force watchman
auto-detection
Merge pull request #2265 from csantero/restart-server

Restart express server and trigger Livereload when a file under /server changes.
add additional case for users (like me) who have watchman installed
Use older node version for appveyor

Looks like a race condition might be biting us:
http://help.appveyor.com/discussions/problems/865-error-running-npm-install
Merge pull request #2566 from raytiley/appveyor-node-version

Use older node version for appveyor
Prevent crashes in http-proxy

This closes #1921.

`connect-restreamer` is fundamentally nuts and rather fragile. It also
makes no sense when we can just avoid the issue entirely by putting
`http-proxy` ahead of `bodyParser`.

People who have already run the proxy generator probably need to be
warned that they won't benefit from this bugfix.
Merge pull request #2568 from ef4/proxy-fix

Prevent mangled POST bodies in http-proxy