134: initial commit
134: in progress

Paused development of 134 to write library utility.
libnt: typedef to #define for arith_t

typedef may lead to undefined behavior when used in multiple files (I
haven't researched on this yet so I'm not sure). I could write a shared
header for the headers, but that's just an overkill. #define can do the
same thing without a master header.
libnt: add numbers.h numbers.cpp

The first two utilities defined in numbers: num_length and pwr10.
134: finalize (correct)