tahoe get on DIR2 URis fails

[gdt]

When doing 'tahoe get' and giving a directory URI, I get "302 Found" instead of the bits. Changing DIR2 to SSK gets me bits. There's no good reason not to return the directory contents; 'cat .' on at least BSD shows the bits in the directory. While most people don't want to look ever, and the rest only want to look once in a while, being able to understand directories is key to a deep understanding of how access control works.

Further, the writecaps should be decrypted when the directory is fetched with a writecap.