dkjson: import from https://github.com/SeattleMeshnet/meshbox.git

Signed-off-by: Lars Gierth <larsg@systemli.org>
lua-sha2: import from https://github.com/SeattleMeshnet/meshbox.git

Signed-off-by: Lars Gierth <larsg@systemli.org>
lua-bencode: import from https://github.com/SeattleMeshnet/meshbox.git

Signed-off-by: Lars Gierth <larsg@systemli.org>
lua-sha2: clean up makefile

Signed-off-by: Lars Gierth <larsg@systemli.org>
Merge pull request #265 from berlinmeshnet/meshbox

Import dkjson, lua-bencode, and lua-sha2