The SLU features library consists of two- and three- dimensional
feature vectores we use to compute grounded word meanings.  There are
several families of features depending on the type of the grounding
(e.g., path, prism, and whether it is 2d or 3d.)

Type "make" to build the library.  All built files will go in the
"build" directory unless the BUILD_PREFIX environment variable is set.

The library is written in C for speed but is designed to be called
from python.  It includes swig wrapperes and python types for many of
its arguments (e.g., Prisms, which are a three dimensional object that
consists of a polygon with height.)  

The library also includes computational geometry libraries for 2d and
3d (called math2d and math3d), designed to be called from C.