Capitalize the constructor. Fixes #31

update demo

Propose using ChaCha12. Closes #19

Specify how to generate a 0-1 value, per Rust's algo. Closes #20

Math.seededPRNG should be a constructor. Closes #27

Several tweaks: switch to just taking the seed arg directly; give .se…

Commit to UInt8Array as the seed type. Closes #18

Add a FAQ to the README about adding additional methods.

Commit to the seed being reflected as a BigInt