Fix some compilation errors on Windows

Docs/how_to_build_on_windows.md

@@ -1,5 +1,11 @@
 <h1>How to build CARLA on Windows</h1>
 
+!!! important
+    Since version 0.9.0 the build system changed, the instructions in this
+    document are no longer valid. While we work on fixing this, we recommend
+    either compile Carla on Linux or switch to the `stable` branch. Sorry for
+    the inconvenience.
+
 <h3>Necessary software</h3>
 - [Git](https://git-scm.com/downloads)
 - [Make](http://gnuwin32.sourceforge.net/downlinks/make-bin-zip.php)
@@ -22,7 +28,7 @@ You have different options:
 - [Enable a 64-Bit Visual C++ Toolset on the Command Line](https://msdn.microsoft.com/en-us/library/x4d2c09s.aspx) (the instructions will depend on the version of VS that you have).
 
 !!! note
-    Take care if you have **Cygwin** installed. This could cause the errors like  
+    Take care if you have **Cygwin** installed. This could cause the errors like
     `/usr/bin/sh: rd: command not found` While executing `Reuild.bat`.
 
 <h3>Clone the repository</h3>

LibCarla/source/test/util/Message.cpp

@@ -6,6 +6,8 @@
 
 #include "Message.h"
 
+#include <boost/random/independent_bits.hpp>
+
 #include <climits>
 #include <random>
 
@@ -21,7 +23,7 @@ namespace message {
   shared_message make_random(size_t size) {
     if (size == 0u)
       return make_empty();
-    using random_bytes_engine = std::independent_bits_engine<
+    using random_bytes_engine = boost::random::independent_bits_engine<
         std::random_device,
         CHAR_BIT,
         unsigned char>;

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Actor/ActorDispatcher.cpp

@@ -38,7 +38,7 @@ TPair<EActorSpawnResultStatus, FActorView> FActorDispatcher::SpawnActor(
     const FTransform &Transform,
     FActorDescription Description)
 {
-  if ((Description.UId == 0) || (Description.UId > SpawnFunctions.Num()))
+  if ((Description.UId == 0u) || (Description.UId > static_cast<uint32>(SpawnFunctions.Num())))
   {
     UE_LOG(LogCarla, Error, TEXT("Invalid ActorDescription \"%s\" (UId=%d)"), *Description.Id, Description.UId);
     return MakeTuple(EActorSpawnResultStatus::InvalidDescription, FActorView());

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Util/ScopedStack.h

@@ -7,6 +7,7 @@
 #pragma once
 
 #include <deque>
+#include <memory>
 
 /// A stack to keep track of nested scopes.
 template <typename T>