Updated the MWC32 lag 2 generator.
 - Now using specific width integer types
 - New function rnd_closed() which returns [0,1]
 - Other improvements
Removed the MWC32 lag 5 generator.
Renamed the MWC32 lag 2 generator.
Small cleanup of the MWC32 lag 2 generator.
Added a MWC32 lag 3 generator.
Added a MWC60 lag 2 generator.
Added a MWC60 lag 3 generator.
Updated the readme.
Changed rnd_dist_normal() to use the Marsaglia polar method.
Updated the LCG96 generator.
Fixed a bug in the MWC32 lag 2 generator.
 - Forgot to use the new macros in two places.
Updated the comments on the LCG96 generator and changed the code to
 reflect the comments.
rnd_init() should take an unsigned long instead of an uint32_t.
 - Updated all generators to take an unsigned long.
Add the ability to get and set the whole state for each generator.
Changed rnd_unsigned() to return an unsigned long.
Renamed the function rnd_unsigned() to rnd_number().
Added the function rnd_number_max() to get the maximum possible
 value returned by rnd_number().