Update Bluewing Server to build 20

Also updated README. See 53caf1b.

Author: SortaCore

README.md

@@ -1,14 +1,7 @@
 # bluewing-cpp-server
-An example of Lacewing Blue (Bluewing) implementation of Lacewing Relay protocol as a server.
+An example of Lacewing Blue (Bluewing) implementation of Lacewing Relay protocol as a server.  
 Windows EXE using Visual Studio. Full C++ speed, with no trace of Clickteam Fusion.
-Bluewing Server Full Powah!
-
-# Multi-platform note
-While this repository is a Visual Studio and Windows based server, Blue liblacewing should be usable on other compilers (e.g. GCC) and on other POSIX-based platforms (e.g. Linux flavours). If you get any issues compiling Bluewing itself on non-Windows, or using non-Visual Studio, feel free to create an issue or pull request.
-
-# License
-This is **MIT license**, so you're free to use personally, commercially, or sell your variant of this, but you should include a notice that you retrieved it from this repository.
-
+ 
 # Features
 * This server is compatible with clients that use Lacewing Relay protocol.
 * Optional Flash policy hosting, and auto-generates a policy file for the Lacewing port.
@@ -22,3 +15,17 @@ The server is compatible with any of the following (and any combination):
 * client programs that are made in Clickteam Fusion 2.5 or Multimedia Fusion 2.0
 * Fusion 2.0/2.5 clients for Windows, Android, and SWF/Flash
 * Lacewing Relay and Lacewing Blue Fusion extensions (Blue is highly recommended for client, as it is more recent)
+
+# Tools needed to edit this source
+You will need Visual Studio 2017+, with Windows XP support add-on.
+* To add it to your VS install, run the Visual Studio Installer, select More > Modify, and under Individual Components tab, enable C++ Windows XP Support for VS 2017 (v141) tools.  
+(Note that VS 2017 XP is the latest XP, so you want VS 2017 XP support even if you're using VS 2019.)
+* Alternatively, XP support requirement can be removed in half a minute; simply switch the compiler under Project Properties > General > Platform Toolset, from v141_xp to v121 (if you're using VS 2017) or v141 (if VS 2019).
+
+Due to use of C++17 features, like std::string_view, VS 2015 is not supported.
+
+# Multi-platform note
+While this repository is a Visual Studio and Windows based server, Blue liblacewing should be usable on other compilers (e.g. GCC) and on other POSIX-based platforms (e.g. Linux flavours). If you get any issues compiling Bluewing itself on non-Windows, or using non-Visual Studio, feel free to create an issue or pull request.
+
+# License
+This is **MIT license**, so you're free to use personally, commercially, or sell your variant of this, but you should include a notice that you retrieved it from this repository.