Hello again, sorry for the delay - I had some holiday time off
that couldn't wait ;-)

I've modified the ob-tangle.el file for the main tangling and
detangling functions.  Most importantly, both functions can now
exchange information from the source Org mode file to the target
remote tangle file in either direction, depending on whether the
source Org file has `:tangle-sync <action>' in the header.

The action is one of:

- "export" = always transmit information from the source Org mode
             block to the target remote file.
- "import" = always transmit information from the target remote
             file to the source Org mode block.
- "skip" = skip the block.
- "both" = transmit information from source block to target block
           or target block to source, depending on whether the
           tangle or detangle is called from the source buffer or
           the target buffer respectively.

These functions work at the whole buffer and at the per-block
level.  The `org-babel-tangle-sync' functions automate this
process by hooking into the `after-save-hook' and tangling /
detangling the current block.

I feel that I should write what the main motivation for this is:
Dotfiles that are always in sync with the org-mode files they
stem from.

Hope this turns into something big!
Best,

Mehmet