Split up gulpfile.js into directories.
Rename server/index.js to server.js.

Then it can be started with `npm start`

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# rebase in progress; onto 40292c5
# You are currently editing a commit while rebasing branch 'feature/refactor-gulp' on '40292c5'.
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# Changes to be committed:
#	modified:   package.json
#	renamed:    server/index.js -> server/server.js
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Document dir structure in README.
Add commands to README.
Rename default to dist task.
Add utils/pkg module.
jshint: Allow function use before definition.
Reorganize paths.
Use paths in clean task.
Use paths in server task.
Generate production package.json.
Update scripts in package.json.
Delete gulp task 'watch' for now.

To be implemented later.
Document each gulp task.
Skip sourcemaps for now.

Will be implemented later.
Combine own js to bundle.js.