`read_pomdp` doesn't appear to fully implement the `.pomdp` spec.

[jmuchovej]

The spec outlines that one can use start: to designate what would be initialstate. Additionally, there are a variety of keywords for start that can be used to modify the distribution of initialstate.

I need to dig further into this, and I'll probably prep some fixes for it, but figured I'd flag it now.

[jmuchovej]

Just looked through the code in more detail. Turns out, start: isn't considered, at all. Thus, folks can't specify an initial state distribution (ergo it's uniform across all states).

I'll probably start working on this once I finish up the tests in #13.