Allow installation into subdirectories of Ships

[dbent]

Fixes #1134, allowing install_to directives to specify Ships/VAB or Ships/SPH to install into those subdirectories. We still don't allow mods to create directories within Ships though.

Still needs:

• Tests
• Documentation Update

This would require a bump to the spec_version to v1.12.

[dbent]

Tests done. Documentation done in #1244.

This isn't as useful as I thought, because I forgot we can't actually rename files/folders. So you either have to specify all the files explicitly or the package has to have the right Ships/(VAH|SPH) structure. It would be nice to have an install_as clause so you could do something like:

{
    "spec_version": "v1.x",
    "identifier": "AwesomeMod",
    "install": [
        {
            "file": "ExampleShips",
            "install_as": "Ships/VAB"
        }
    ]
}

Then all the contents of ExampleShips would be dumped into Ships/VAB.

[pjf]

Given how often users manage to delete their SPH/VAB/@thumbs directories, we should re-create those if required. (Not a requirement for this PR, but noting it down because it just came up on IRC...)

[pjf]

Are the files in @thumbs auto-generated by KSP? Right now I presume we allow installation to it (because it exists, and we'll copy things from Ships), so it would make sense to allow it to be specified as an install target as well.

[pjf]

Aha, @thumbs is auto-generated by KSP (thanks @Postremus). This is on my review queue. :)

[pjf]

Tested on KSP-CKAN/NetKAN#1837 , and seems to be working fine. Merge in progress. :)

[pjf]

Merged with great thanks!