sqlite and misc optimizations:

* exponentially slow upload handshakes caused by lack of rd+fn
   sqlite index; became apparent after a volume hit 200k files
* listing big folders 5% faster due to `_quotep3b`
* optimize `unquote`, 20% faster but only used rarely
* reindex on startup 150x faster in some rare cases
   (same filename in MANY folders)

the database is now around 10% larger (likely worst-case)

tests/test_utils.py

@@ -0,0 +1,38 @@
+#!/usr/bin/env python3
+# coding: utf-8
+from __future__ import print_function, unicode_literals
+
+import unittest
+
+from copyparty.__main__ import PY2
+from copyparty.util import w8enc
+from tests import util as tu
+
+
+class TestUtils(unittest.TestCase):
+    def cmp(self, orig, t1, t2):
+        if t1 != t2:
+            raise Exception("\n%r\n%r\n%r\n" % (w8enc(orig), t1, t2))
+
+    def test_quotep(self):
+        if PY2:
+            raise unittest.SkipTest()
+
+        from copyparty.util import _quotep3, _quotep3b, w8dec
+
+        txt = w8dec(tu.randbytes(8192))
+        self.cmp(txt, _quotep3(txt), _quotep3b(txt))
+
+    def test_unquote(self):
+        if PY2:
+            raise unittest.SkipTest()
+
+        from urllib.parse import unquote_to_bytes as u2b
+
+        from copyparty.util import unquote
+
+        for btxt in (
+            tu.randbytes(8192),
+            br"%ed%91qw,er;ty%20as df?gh+jkl%zxc&vbn <qwe>\"rty'uio&asd&nbsp;fgh",
+        ):
+            self.cmp(btxt, unquote(btxt), u2b(btxt))