Yet another dtypes and Windows bug

[JavadocMD]

As reported by our new Windows users, initializer.py is raising an Exception (seemingly when running some of the basic examples?) related to numpy int64/int32 mismatches.

This is likely caused by Windows interpreting np.integer differently than other platforms. np.floating is also problematic, and initializer.py is using both.

[JavadocMD]

Believe this was my oversight, thinking I could use np.integer and np.floating to accept any integral or any decimal numbers (respectively). But with more research they clearly do not function that way; it just happened to work for the cases I'd tried thus far.

For the time being, I'll make these checks more strict -- replacing them with np.int64 and np.float64.