Add class ExecuteCommand.
This class has the following methods:

  exe - execute commands on the server.

Method 'exe' has the folloving options :
  flavor='512'
  image='cirros-0.3.1-x86_64-uec'
  cmd='echo "Hello, world"'

Method 'exe' find for the server with the appropriate parameters
(image and flavor) and if not found, it creates a new one and it
runs command.