support data structure functions

[fiji-flo]

• tuple: Takes an arbitrary list of items and returns a slice of items. Its
  tuple-ish properties are mainly gained through the template idiom, and not
  through an API provided here. WARNING: The implementation of tuple will
  change in the future.
• list: An arbitrary ordered list of items. (This is prefered over tuple.)
• dict: Takes a list of name/values and returns a map[string]interface{}.
  The first parameter is converted to a string and stored as a key, the
  second parameter is treated as the value. And so on, with odds as keys and
  evens as values. If the function call ends with an odd, the last key will
  be assigned the empty string. Non-string keys are converted to strings as
  follows: []byte are converted, fmt.Stringers will have String() called.
  errors will have Error() called. All others will be passed through
  fmt.Sprtinf("%v").