Changes from 11/12/2014.

Changelog:
2014.12.11:
- Changed our implementation of "setBackgroundHandling()" and "moveBackgroundHandling()" in
  "BasicTaskScheduler" to check for (and disallow) socket numbers >= FD_SETSIZE,
  because <sys/select.h> has a bug (at least, in most systems) that causes buffer overflow
  in this case.  (Thanks to Michel Promonet for pointing this out.)