cosmit: newline in comment
slightly pretty-up toString for Pomdp objects
fix bug re: indexing when building a prob_matrix
cosmit: update comments
use braces in loops with multiline blocks
fix issue #6.

i don't know what these lines were doing, but it seems to be related to handling multiple reward spec types in a single file. let's not support this for now.
cosmit: remove old comment
cosmit: whitespace