labcomm_internal_encode, this triggered lots of changes to handling of 
stacked writer allocation. Twoway example is not finished yet.

Start of adding GPLv3 licensensing.

Labcomm cleanup (still more to do)

Added dynamic macros and code for dynamic arrays indexed by signature
index.

Somewhat improved error handling in readers.

Changed reader/writer interface to simplify stacking (example will 
be forthcoming).

fd_reader/writer more robust: no dependency on 'int *fd' to be live
while the reader/writer is in use).

encoder indices (linker magic provided).