POST to /alexa/format-intents fails on Bluemix

[hardillb]

When Node-RED is installed using the boilerplate on Bluemix is moves the editor (httpAdminRoot) to /red.

This means the Skill Config node is trying to POST to /red/alexa/format-intents instead of /alexa/format-intents which it is where it's actually bound

[hardillb]

The fix is to take the / off the start of the URL at https://github.com/mattotodd/node-red-contrib-alexa/blob/master/alexa.html#L76