Trying to get the C/R code to compile again.  (recv_*_nb)
This patch changes all recv/recv_buffer occurrences in the C/R code
to recv_nb/recv_buffer_nb.
The old code is still there but disabled using ifdefs (ENABLE_FT_FIXED).
The new code compiles but does not work.

Changes from V1:
* #ifdef out the code (so it is preserved for later re-design)
* marked the broken C/R code with ENABLE_FT_FIXED

Changes from V2:
* only #ifdef out the code where the behaviour is changed
  (used to be blocking; now non-blocking)
Trying to get the C/R code to compile again. (send_*_nb)
This patch changes all send/send_buffer occurrences in the C/R code
to send_nb/send_buffer_nb.
The new code compiles but does not work.

Changes from V1:
* #ifdef out the code (so it is preserved for later re-design)
* marked the broken C/R code with ENABLE_FT_FIXED

Changes from V2:
* just replace the blocking calls with the non-blocking calls
* all #ifdef's introduced in V1 are gone
* send_* returns error code or ORTE_SUCCESS (not the number of bytes)