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/graph-to-graphviz.py

@@ -1,39 +0,0 @@
-from graphviz import Digraph
-from collections import deque
-from fixtures import weighted_graph
-
-# There are three ways to model a graph:
-# 1. Edge list: [(Vertex, Vertex)]
-# 2. Neighbors table: Map(Vertex, [Vertex])
-# 3. Adjacency matrix: [[Boolean]]
-#
-# The following graph is a neighbors table.
-
-
-# to_graphviz :: Vertex -> Map(Vertex, [(Vertex, Weight)]) -> String
-def to_graphviz(start, g):
-    """Compiles the graph into GraphViz."""
-    d = Digraph()
-    q = deque()
-    seen = set()
-
-    q.append(start)
-
-    while q:
-        v = q.popleft()
-        if v in seen:
-            continue
-        d.node(v, label=v)
-
-        for w, x in g[v]:
-            d.edge(v, x, label=str(w))
-            q.append(x)
-        seen.add(v)
-
-    return d.source
-
-
-with open('/tmp/test.gv', 'w') as f:
-    src = to_graphviz('a', weighted_graph)
-    f.write(src)
-    print('/tmp/test.gv created!')