Tidying up switch-to-relevant-buffer, updating docs, and adding check against ambiguous switch.
Merge pull request #451 from jonpither/tidy

Tidying up switch-to-relevant-buffer.
Correct key-bindings in README
Mention the clojure-doc Emacs tutorial
Add logo to README
Refine title
Better wording
Update an error message
Use a more descriptive name
Add logo & credit @ndr-qef for its creation
Use bigger logo in the README
Clean up logo SVG code.

Remove Illustrator-generated junk elements.
Merge pull request #456 from ndr-qef/logo

Slightly cleaner logo SVG file.
Showing endpoint host when no project directory.