Tidy up structure of briefcase

I had a spare fifteen minutes and decided that I should tidy up my
monorepo. The work of tidying up is not finished; this is a small step in the
right direction.

TL;DR
- Created a tools directory
- Created a scratch directory (see README.md for more information)
- Added README.md to third_party
- Renamed delete_dotfile_symlinks -> symlinkManager
- Packaged symlinkManager as an executable symlink-mgr using buildGo

data_structures_and_algorithms/mesh-message.py

@@ -1,97 +0,0 @@
-import unittest
-from collections import deque
-
-
-################################################################################
-# Solution
-################################################################################
-# get_path :: G(V, E) -> V -> V -> Maybe([V])
-def get_path(g, src, dst):
-    q = deque()
-    result = None
-    seen = set()
-    q.append(([], src))
-
-    if src not in g or dst not in g:
-        raise Exception
-
-    while q:
-        p, node = q.popleft()
-
-        seen.add(node)
-
-        if node == dst:
-            if not result:
-                result = p + [node]
-            elif len(p + [node]) < len(result):
-                result = p + [node]
-        else:
-            if node not in g:
-                raise Exception
-            for x in g.get(node):
-                if not x in seen:
-                    q.append((p + [node], x))
-
-    return result
-
-
-################################################################################
-# Tests
-################################################################################
-class Test(unittest.TestCase):
-    def setUp(self):
-        self.graph = {
-            'a': ['b', 'c', 'd'],
-            'b': ['a', 'd'],
-            'c': ['a', 'e'],
-            'd': ['a', 'b'],
-            'e': ['c'],
-            'f': ['g'],
-            'g': ['f'],
-        }
-
-    def test_two_hop_path_1(self):
-        actual = get_path(self.graph, 'a', 'e')
-        expected = ['a', 'c', 'e']
-        self.assertEqual(actual, expected)
-
-    def test_two_hop_path_2(self):
-        actual = get_path(self.graph, 'd', 'c')
-        expected = ['d', 'a', 'c']
-        self.assertEqual(actual, expected)
-
-    def test_one_hop_path_1(self):
-        actual = get_path(self.graph, 'a', 'c')
-        expected = ['a', 'c']
-        self.assertEqual(actual, expected)
-
-    def test_one_hop_path_2(self):
-        actual = get_path(self.graph, 'f', 'g')
-        expected = ['f', 'g']
-        self.assertEqual(actual, expected)
-
-    def test_one_hop_path_3(self):
-        actual = get_path(self.graph, 'g', 'f')
-        expected = ['g', 'f']
-        self.assertEqual(actual, expected)
-
-    def test_zero_hop_path(self):
-        actual = get_path(self.graph, 'a', 'a')
-        expected = ['a']
-        self.assertEqual(actual, expected)
-
-    def test_no_path(self):
-        actual = get_path(self.graph, 'a', 'f')
-        expected = None
-        self.assertEqual(actual, expected)
-
-    def test_start_node_not_present(self):
-        with self.assertRaises(Exception):
-            get_path(self.graph, 'h', 'a')
-
-    def test_end_node_not_present(self):
-        with self.assertRaises(Exception):
-            get_path(self.graph, 'a', 'h')
-
-
-unittest.main(verbosity=2)