fix some file extensions

Task/Set/CoffeeScript/set.coffeescript

@@ -1,85 +0,0 @@
-# For ad-hoc set features, it sometimes makes sense to use hashes directly,
-# rather than abstract to this level, but I'm showing a somewhat heavy
-# solution to show off CoffeeScript class syntax.
-class Set
-  constructor: (elems...) ->
-    @hash = {}
-    for elem in elems
-      @hash[elem] = true
-
-  add: (elem) ->
-    @hash[elem] = true
-
-  remove: (elem) ->
-    delete @hash[elem]
-
-  has: (elem) ->
-    @hash[elem]?
-
-  union: (set2) ->
-    set = new Set()
-    for elem of @hash
-      set.add elem
-    for elem in set2.to_array()
-      set.add elem
-    set
-
-  intersection: (set2) ->
-    set = new Set()
-    for elem of @hash
-      set.add elem if set2.has elem
-    set
-
-  minus: (set2) ->
-    set = new Set()
-    for elem of @hash
-      set.add elem if !set2.has elem
-    set
-
-  is_subset_of: (set2) ->
-    for elem of @hash
-      return false if !set2.has elem
-    true
-
-  equals: (set2) ->
-    this.is_subset_of(set2) and set2.is_subset_of this
-
-  to_array: ->
-    (elem for elem of @hash)
-
-  each: (f) ->
-    for elem of @hash
-      f(elem)
-
-  to_string: ->
-    @to_array()
-
-run_tests = ->
-  set1 = new Set("apple", "banana") # creation
-  console.log set1.has "apple" # true (membership)
-  console.log set1.has "worms" # false (membership)
-
-  set2 = new Set("banana", "carrots")
-  console.log set1.union(set2).to_string() # [ 'apple', 'banana', 'carrots' ] (union)
-  console.log set1.intersection(set2).to_string() # [ 'banana' ] (intersection)
-  console.log set1.minus(set2).to_string() # [ 'apple' ] (difference)
-
-  set3 = new Set("apple")
-  console.log set3.is_subset_of set1 # true
-  console.log set3.is_subset_of set2 # false
-
-  set4 = new Set("apple", "banana")
-  console.log set4.equals set1 # true
-  console.log set4.equals set2 # false
-
-  set5 = new Set("foo")
-  set5.add "bar" # add
-  console.log set5.to_string() # [ 'foo', 'bar' ]
-  set5.remove "bar" # remove
-  console.log set5.to_string() # [ 'foo' ]
-
-  # iteration, prints apple then banana (order not guaranteed)
-  set1.each (elem) ->
-    console.log elem
-
-run_tests()