add Sparkle update framework
refactor and add a vm service provider
lots of refactoring; added VirtualBox service provider and machine info classes
Implement auto-update functionality
Merge remote-tracking branch 'devturf/add-vm-provider' into develop
refactoring/cleanup and add 'all machines' commands
Merge remote-tracking branch 'devturf/add-global-commands' into develop
re-arrange methods
redesign theme images and include retina images for all images
remove unnecessary file .m file
update gitignore
Merge branch 'sparkle-auto-update' into develop
re-arrange methods
fix alignment of preferences window text
update plist for Sparkle updater functionality
bump to version 1.5.0
Merge branch 'release-1.5.0' into develop