merkle is broken and incomplete

...it should have never been added. Will add it back once it works.
Point: toJSON/fromJSON/toString/fromString

Every class should have a toJSON/fromJSON function, and for many of them a
toString/fromString function is also appropriate. To create these functions I
also added a copy method for Point, and I also modify .fromX to use the copy
function, and I also ensure the BN copy method also works in the same way for
internal consistency.
put version # in bundle
remove commented-out code

...these lines were supposed to represent future components of the library that
would one day exist. Enough of the library exists now that this stuff is
obsolete.
add BN fromNumber, and also add tests for toNumber

toNumber hadn't been tested. now it is.
move toNumber/fromNumber near the other to/froms