hardcode Ubuntu image in cloud preferences
removed references to the IAS server
return the list of cloud servers as a property
close cloud server connections when gns3 exits
Merge pull request #46 from planctechnologies/gns-132

Gns 132 Remove IAS (Image Access Server) code
Merge pull request #47 from planctechnologies/gns-136

Gns 136 gui won't exit when telnet session open to device
utility methods for shutting down cloud servers
remove nodes when removing instances
remove devices when removing instances
do nothing if server is None
Merge pull request #48 from planctechnologies/gns-133

Gns 133 Deleting an instance orphans devices on canvas
Grammar fixes
Merge branch 'dev' of github.com:planctechnologies/gns3-gui into dev
Merge branch 'dev' into gns-61