Enable management of keypairs and Floating IPs

Extended to enable management of Floating IPs and Keypairs:

#### Floating IPs
* Can query for *available* floating IPs for reuse with `list_floating_ips.rb`
* Assign a new floating IP to project with `create_floating_ip.rb`
* Assign a floating IP to a server using `create_floating_ip.rb`

#### Keypairs
* Query for keypairs with `list_keypairs.rb`
* Create new keypair for user with `create_keypair.rb`
* Assign keypair to server with change to `list_keypairs.rb`