Closes #97 - Create Range class for Fluo API

Pull request for #97
I was thinking String related methods could be at the type layer, where a user can plug in an encoder (instead of always specifying an encoding).   A bit ago I had tried to make the basic API only take ByteSequence.

However, I can understand the convenience of having the methods that accept String.   If we are going to have String methods in the basic API, it should be consistent.  Should avoid some methods only taking Bytes while others take Bytes and String.  Also methods that take String should document that the Strings will be utf-8 encoded, this could be done at the class or package level if its wide spread.