Release 1.1.0

• A simple implementation of tuple, an
  immutable, fixed-length list/array/vector-like data structure.
• FinalStruct, a variation on Ruby's OpenStruct in which all fields are "final" (meaning
  that new fields can be arbitrarily added but once set each field becomes immutable).
• FinalVar, a thread safe object that holds a single value and is "final" (meaning
  that the value can be set at most once after which it becomes immutable).