Fixes some issues with VirtualBox support.
Merge pull request #43 from planctechnologies/dev

Download IOS images from Cloud Files to a cloud instance
Add REUSE flag to socket when scanning for unused ports.
New Telnet server for VirtualBox.
Fixes issues with VirtualBox Telnet server on Windows.
Fixes missing cloud settings on Windows.
Check for duplicate node names in Preferences.
Add detection of qemu and qemu.exe binaries.