Splice ./universe directory into ./

Manually merging:
- README.md: I added the description from universe/README.md into the heading of
  dotfiles/README.md.
- .envrc: dotfiles/.envrc was a superset of universe/.envrc
- .gitignore: Adding some of the ignored patterns from universe/.gitignore to
  dotfiles/.gitignore

Everything else here should be a simple rename.

universe/data_structures_and_algorithms/kth-to-last.py

@@ -1,82 +0,0 @@
-import unittest
-
-
-################################################################################
-# Solution
-################################################################################
-def length(x):
-    if not x:
-        return 0
-    else:
-        count = 1
-        while x:
-            x = x.next
-            count += 1
-        return count
-
-
-def kth_to_last_node(k, x):
-    hops = length(x) - 1
-    dest = hops - k
-
-    if k == 0:
-        raise Exception("Our God doesn't support this kind of behavior.")
-
-    if dest < 0:
-        raise Exception('Value k to high for list.')
-
-    while dest > 0:
-        x = x.next
-        dest -= 1
-
-    return x
-
-
-################################################################################
-# Tests
-################################################################################
-class Test(unittest.TestCase):
-    class LinkedListNode(object):
-        def __init__(self, value, next=None):
-            self.value = value
-            self.next = next
-
-        def get_values(self):
-            node = self
-            values = []
-            while node is not None:
-                values.append(node.value)
-                node = node.next
-            return values
-
-    def setUp(self):
-        self.fourth = Test.LinkedListNode(4)
-        self.third = Test.LinkedListNode(3, self.fourth)
-        self.second = Test.LinkedListNode(2, self.third)
-        self.first = Test.LinkedListNode(1, self.second)
-
-    def test_first_to_last_node(self):
-        actual = kth_to_last_node(1, self.first)
-        expected = self.fourth
-        self.assertEqual(actual, expected)
-
-    def test_second_to_last_node(self):
-        actual = kth_to_last_node(2, self.first)
-        expected = self.third
-        self.assertEqual(actual, expected)
-
-    def test_first_node(self):
-        actual = kth_to_last_node(4, self.first)
-        expected = self.first
-        self.assertEqual(actual, expected)
-
-    def test_k_greater_than_linked_list_length(self):
-        with self.assertRaises(Exception):
-            kth_to_last_node(5, self.first)
-
-    def test_k_is_zero(self):
-        with self.assertRaises(Exception):
-            kth_to_last_node(0, self.first)
-
-
-unittest.main(verbosity=2)