Type used for number of samples is inconsistent

[joshbarrass]

In some places (e.g. readsamples in the state object), samples are defined as an int. Elsewhere, they are defined as 16-bit integers or 64-bit integers. We should figure out which type is going to be reasonable and make it consistent throughout the codebase.

[joshbarrass]

From some back of the notebook calculations, using long should be fine. This would guarantee a minimum of 32-bits, so up to 2147483647 samples (or 4294967295 if using unsigned).