Planned - short term:
- avoid as much as possible memory copies (I probably will change the internal
  encoding of messages)
- optional escape sequence in the command line (usefullness to be discussed)

Planned - long term:
- adaptive window

Given up (see construct tests for some of these cases):
- efficient transfer of taktuk engine - actually not efficient (using the way I
  had in mind)
- sendv/recvv of different sizes - given up, not meaningful to TakTuk
- reduction of the number of concatenations - no easy gain still under
  investigation
