Coreccted LabComm.py

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)

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).

Updated wiki_example to use StreamReader. 

changed generated length to be without user_id field + started changing the sig_parser to build signature_t objects