Use snapshot to get latest pointer_traits

.appveyor.yml

@@ -17,9 +17,9 @@ environment:
 
 install:
   - cd c:\projects
-  - curl -sSL -o boost.7z https://dl.bintray.com/boostorg/release/1.66.0/source/boost_1_66_0.7z
+  - curl -sSL -o boost.7z https://dl.bintray.com/boostorg/master/boost_1_67_0-snapshot.7z
   - 7z x boost.7z
-  - set BOOST_ROOT=c:\projects\boost_1_66_0
+  - set BOOST_ROOT=c:\projects\boost_1_67_0
   - rd /s /q %BOOST_ROOT%\boost\unordered
   - cd %BOOST_ROOT%\tools\build
   - cmd /c bootstrap

.travis.yml

@@ -62,7 +62,8 @@ before_script:
                 snapshot=develop
             fi
         else
-            snapshot=stable
+            #snapshot=stable
+            snapshot=master
         fi
 
         # Set download_url for snapshot