Moar polish, moar mods

• More GUI improvements
• Linux compatibility fixes
• Allow installs to Tutorials and GameRoot
• ckan upgrade implemented
• Extra support for mods hosted on KerbalStuff

GUI ready for lift-off!

• We have a GUI! ckan gui or just ckan will start it
  (thanks to @AlexanderDzhoganov)
• This breaks existing CKAN registries. You'll have to wipe your
  existing CKAN dir if using CKAN 0.04 or earlier.
• Users are only given KSP mods which work with their version of KSP.
• Relationships (suggests, depends, recommends, conflicts) implemented.
• (Internal/Meta) Debian licenses spec adopted.
• Many, many minor bugfixes and improvements.

Sub-orbital CKAN

• Locates Steam on OSX
• ckan update implented; fetch the CKAN online!
• ckan available lists available mods.
• ckan install now installs from the network.
• ckan show dies with less mess when a mod is not installed.
• The --ksp=... switch can be added to any option, specifying where KSP is installed.
• ckan config gamedir /path/to/gamedir sets the default gamedir location.
• --debug and --verbose can be added to any command, to see more of what's happening inside.
• KSP version is auto-detected.
• ckan by itself displays help.

Fewer bugs when downloading.

• Less pain from partially downloaded files.
• Better advice to Linux/Mono users who are missing certificates.
• New command ckan clean to clear the file cache.

Let's test github releases!

This exists primarily as a test of the github release system; in particular, we're testing bundled executables.

You can try to use this if you like, because bits do work, but it's pretty filed with bugs (which you should report at https://github.com/pjf/CKAN/issues ).