py3++, multidict fixes

This commit improves Python 3 compatibility and fixes two multidict
issues:

 1. Headers.items(multi=True) now decodes fields
 2. MultiDict.clear(item) has been removed, as Python's
    MutableMapping already defines .clear() with different
    semantics. This is confusing for everyone who expects a
    dict-like object. `.pop("attr", None)` is not fantastic,
    but it's the Python way to do it.

2 files changed, 12 insertions, 3 deletions

diff --git a/netlib/http/headers.py b/netlib/http/headers.py
index f052a53b..413add87 100644
--- a/netlib/http/headers.py
+++ b/netlib/http/headers.py
@@ -148,6 +148,15 @@ class Headers(multidict.MultiDict):
         value = _always_bytes(value)
         super(Headers, self).insert(index, key, value)
 
+    def items(self, multi=False):
+        if multi:
+            return (
+                (_native(k), _native(v))
+                for k, v in self.fields
+            )
+        else:
+            return super(Headers, self).items()
+
     def replace(self, pattern, repl, flags=0):
         """
         Replaces a regular expression pattern with repl in each "name: value"
diff --git a/netlib/http/http2/utils.py b/netlib/http/http2/utils.py
index 4c01952d..164bacc8 100644
--- a/netlib/http/http2/utils.py
+++ b/netlib/http/http2/utils.py
@@ -7,9 +7,9 @@ def parse_headers(headers):
     scheme = headers.get(':scheme', 'https').encode()
     path = headers.get(':path', '/').encode()
 
-    headers.clear(":method")
-    headers.clear(":scheme")
-    headers.clear(":path")
+    headers.pop(":method", None)
+    headers.pop(":scheme", None)
+    headers.pop(":path", None)
 
     host = None
     port = None