Fix powify.dev utility webservice

powify utils install was cloning powify, the gem not the web app. Fix
that by changing clone url.
update app create command to avoid over-creation.
Merge pull request #23 from incazteca/master

Help displayed if no arguments passed
Merge pull request #24 from kayhide/avoid-over-creation

Update app create command to avoid over-creation.
Merge pull request #22 from bytesplit/master

Fix powify.dev utility webservice
Release v0.9.2
Add xip command to open app on xip.io

xip.io is a service that forwards requests to the local IP address
specified in the domain. So requests to
http://your-pow-app.your-local-ip.xip.io will open your POW app,
assuming the computer accessing the URL has access to your local IP.
This allows one to, for instance, test a POW app from a mobile device
on the same local network.

The new command functions just like `powify browse` except that it
adds the local ip address and the xip.io extension to the URL.
Merge pull request #28 from jakeonrails/xip

Add xip command to open app on xip.io
Prevent error when command does not exist
Merge pull request #29 from repinel/master

Prevent error when command does not exist