Handle multiline strings with '# noqa'

In Flake8 2.x we allowed people to use # noqa at the end of a multiline
string to ignore errors inside the string (e.g., E501). Being blissfully
ignorant of this, I never accounted for it in Flake8 3. This fixes the
oversight and allows multiline statements to have the # noqa at the end.

Closes #177

docs/source/release-notes/3.0.1.rst

@@ -0,0 +1,10 @@
+3.0.1 -- 2016-07-25
+-------------------
+
+- Fix regression in handling of ``# noqa`` for multiline strings.
+  (See also `GitLab#177`_)
+
+
+.. links
+.. _GitLab#177:
+    https://gitlab.com/pycqa/flake8/issues/177

docs/source/release-notes/index.rst

@@ -6,6 +6,7 @@ All of the release notes that have been recorded for Flake8 are organized here
 with the newest releases first.
 
 .. toctree::
+    3.0.1
     3.0.0
     2.6.2
     2.6.1