Make writePrimitive*() and readPrimitive*() methods public.

[aleph-zero]

These utility methods are useful for client code to read/write arrays of
primitive types.

[s1monw]

@aleph-zero why do these methods return Object instead of the actual type?

[aleph-zero]

@s1monw Just trying to make the smallest change that works. I'll change them to return the actual array types.

[s1monw]

++

[aleph-zero]

Ick. I munged my repo. Going to submit a new PR.