Add pagination to streams

[rhyolight]

It takes forever to load the streams HTML view, CSV, or JSON data. For example, the mn-traffic-sensors river has over 6,000 keys: http://data.numenta.org/mn-traffic-sensors/keys.html & http://data.numenta.org/mn-traffic-sensors/keys.json.

This task is to add pagination to the to streams view at http://localhost:8085/<river-name>/keys.html. This goes from /site/templates/keys.html to /site/js/keys.js to /lib/data-server.js:119 (handleRiverStreamsRequest) and aaaaaaaall the way to the Redis client at /lib/redis-client.js.

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• Add pagination options for Redis client getKeys()
• Redis client getKeys() results should be sorted by key
• JSON requests for streams should respect pagination options
• HTML stream view should be paginated

[rhyolight]

@antidata Ever used Redis?