Adjust the demo to work with different slack windows
Adjust the demo to work with different slack windows

The demo now adjusts the number of elements per
window depending on the slack configured. The usage
is submitted an hour into a future to bypass any
time-dependent portions of the demo.

This fixes #113

BetaFood/cf-abacus-dev,nmaslarski/cf-abacus,jsdelfino/x-abacus,pombredanne/cf-abacus,18F/cf-abacus,KRuelY/cf-abacus,jsdelfino/cf-abacus-experiment,cloudfoundry-incubator/cf-abacus,sasrin/cf-abacus,jsdelfino/d-abacus,KRuelY/cf-abacus,kurumai/cf-abacus,sasrin/cf-abacus,KRuelY/cf-abacus,BetaFood/cf-abacus-dev,kurumai/cf-abacus,18F/cf-abacus,rajkiranrbala/cf-abacus,rajkiranrbala/cf-abacus,jsdelfino/x-abacus,jsdelfino/cf-abacus-experiment,nmaslarski/cf-abacus,pombredanne/cf-abacus,danparsons/cf-abacus,rajkiranrbala/cf-abacus,cloudfoundry-incubator/cf-abacus,BetaFood/cf-abacus-dev,nmaslarski/cf-abacus,jsdelfino/d-abacus,jsdelfino/x-abacus,cloudfoundry-incubator/cf-abacus,jsdelfino/cf-abacus-experiment,jsdelfino/d-abacus,jsdelfino/x-abacus,18F/cf-abacus,sasrin/cf-abacus,jsdelfino/d-abacus,pombredanne/cf-abacus,nmaslarski/cf-abacus,danparsons/cf-abacus,pombredanne/cf-abacus,rajkiranrbala/cf-abacus,KRuelY/cf-abacus,danparsons/cf-abacus