runctl: strong-supervisor replaces clusterctl

strong-supervisor's runctl utility replaces strong-cluster-control's
clusterctl utility.
Extend strong-cli with generator-loopback and loopback-sdk-angular-cli
Sample app is now loopback-example-app
v2.6.0-1
Update generated documentation.
Merge pull request #146 from strongloop/feature/runctl

Add `slc runctl` command
Merge pull request #147 from strongloop/feature/prepare-for-lb20

Extend strong-cli with generator-loopback and loopback-sdk-angular-cli
v2.6.0-1