Python 3.7 Support (#447)

* py3.7 fixes:
- add __repr__ to WBException for consistent output in py3.7
- don't raise StopIteration in generator, just return

* ci: add py3.7 builds to travis and appveyor, (don't include in integration test suite for now)

.travis.yml

@@ -4,6 +4,7 @@ python:
   - "2.7"
   - "3.5"
   - "3.6"
+  - "3.7"
 
 dist: xenial
 
@@ -44,4 +45,6 @@ matrix:
       python: "2.7"
     - env: WR_TEST=yes
       python: "3.5"
+    - env: WR_TEST=yes
+      python: "3.7"
 

appveyor.yml

@@ -9,6 +9,9 @@ environment:
     - PYTHON: "C:\\Python35-x64"
     - PYTHON: "C:\\Python36"
     - PYTHON: "C:\\Python36-x64"
+    - PYTHON: "C:\\Python37"
+    - PYTHON: "C:\\Python37-x64"
+
 
 install:        
   - "SET PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%"

pywb/utils/wbexception.py

@@ -7,6 +7,9 @@ class WbException(Exception):
         self.msg = msg
         self.url = url
 
+    def __repr__(self):
+        return "{0}('{1}',)".format(self.__class__.__name__,  self.msg)
+
 # Default Error Code
 #    def status(self):
 #        return '500 Internal Server Error'

pywb/warcserver/index/zipnum.py

@@ -214,9 +214,7 @@ class ZipNumIndexSource(BaseIndexSource):
                 reader.close()
                 if query.page_count:
                     yield self._page_info(0, pagesize, 0)
-                    return
+                return
-                else:
-                    raise
 
         first = IDXObject(first_line)