Added `OS_ACTIVITY_MODE` environment variable to iOS, tvOS and iOS Example.

This environment variable disables all the additional logging information produced by the internal Apple frameworks. This commit should be reverted once Xcode 8 removes all the additional logging.

Alamofire.xcodeproj/xcshareddata/xcschemes/Alamofire iOS.xcscheme

@@ -84,6 +84,13 @@
             ReferencedContainer = "container:Alamofire.xcodeproj">
          </BuildableReference>
       </MacroExpansion>
+      <EnvironmentVariables>
+         <EnvironmentVariable
+            key = "OS_ACTIVITY_MODE"
+            value = "disable"
+            isEnabled = "YES">
+         </EnvironmentVariable>
+      </EnvironmentVariables>
       <AdditionalOptions>
       </AdditionalOptions>
    </LaunchAction>

Alamofire.xcodeproj/xcshareddata/xcschemes/Alamofire tvOS.xcscheme

@@ -84,6 +84,13 @@
             ReferencedContainer = "container:Alamofire.xcodeproj">
          </BuildableReference>
       </MacroExpansion>
+      <EnvironmentVariables>
+         <EnvironmentVariable
+            key = "OS_ACTIVITY_MODE"
+            value = "disable"
+            isEnabled = "YES">
+         </EnvironmentVariable>
+      </EnvironmentVariables>
       <AdditionalOptions>
       </AdditionalOptions>
    </LaunchAction>

Example/iOS Example.xcodeproj/xcshareddata/xcschemes/iOS Example.xcscheme

@@ -61,6 +61,13 @@
             ReferencedContainer = "container:iOS Example.xcodeproj">
          </BuildableReference>
       </BuildableProductRunnable>
+      <EnvironmentVariables>
+         <EnvironmentVariable
+            key = "OS_ACTIVITY_MODE"
+            value = "disable"
+            isEnabled = "YES">
+         </EnvironmentVariable>
+      </EnvironmentVariables>
       <AdditionalOptions>
       </AdditionalOptions>
    </LaunchAction>