IOPort: Do not set ReceiveLatency=0.000001 secs by default anymore.

Explictely setting ReceiveLatency by default during an
IOPort('OpenSerialPort', ...); call meant that the low-
latency setup code on OSX and Linux would always get
executed. Some serial port / serial-over-usb ports do
not support that setting and throw ugly errors. To avoid
this, do not set the parameter anymore by default.

Instead, relevant M-Files specify it now explicitely where
really low latency is needed, e.g., for response boxes,
trigger reception etc.

-> IOPort.mex for 64-Bit Octave on Linux rebuilt.

-> Multiple M-Files updated to accomodate the change, e.g.,
   PsychRTBox, CedrusResponseBox, CMUBox, BitsPlusPlus,
   ReceivingTriggerFromSerialPortDemo, ...