This is currently a very hastily thrown together interface to libstemmer_c,
the C version of Snowball for word stemming from Dr. Martin Porter.

This can replace the R package Rstem in the future and the API is
almost identical. The only difference is that one can specify the 
encoding of the inputs, but don't have to.
 
 * This still needs some work to do the right thing in different places.

In the near future, we will add facilities to have sb_stemmer objects
as external pointers.  This will avoid recreating them and more
importantly ensure they are deleted in the event of an error in the C
code.

The available stemming algorithms can be queried using the R function
getStemLanguages().

Stemming a vector of words is done via wordStem()

