Elimate warnings given by Visual Studio 2013

[donno]

For example:

• warning C4013: 'gettimeofday/strndup/usleep' undefined; assuming extern returning int
  This is caused by a missing a declaration of gettimeofday, strndup and usleep.
• warning C4244: 'function' : conversion from 'int16' to 'uint8', possible loss of data

REAL_PRIO_MUL should be 0.1f instead of just 0.1 to prevent it converting to a double then trying to go back to a float.