Delete references to libsodium/

To avoid confusion until we fixed out if we will change our encryption parameters to match TLS, which would be necessary to support it.

README.md

@@ -83,7 +83,6 @@ Third party language bindings:
   * Clang 3.3 or later
   * Visual Studio 2017 or later
 * OpenSSL 1.1.0 or later
-* libsodium 1.0.16 or later (optional, strongly recommended)
 * Google protobuf (3.0+ recommended, but 2.6.1+ should work)
 * ed25519-donna and curve25519-donna.  We've made some minor changes, so the
   source is included in this project.
@@ -119,41 +118,6 @@ OpenSSL binaries from these installers, which makes building a lot easier. Be
 sure to pick the installers **without** the "Light"suffix. In this instance,
 "Light" means no development libraries or headers.
 
-#### libsodium
-libsodium is an optional dependency, but strongly recommended for performance
-reasons. The curve25519/ed25519 sources in this repository are a slow
-reference implementation, but can act as a fallback if libsodium is
-unavailable for some reason. If you want to build *without* libsodium, just
-add `-DUSE_LIBSODIUM:BOOL=OFF` to your CMake arguments, or
-`-Duse_libsodium=false` if you're using Meson.
-
-If you're building on Linux or Mac, just install the appropriate packages from
-your package manager.
-
-Ubuntu/Debian:
-```
-# apt install libsodium-dev
-```
-
-Arch Linux:
-```
-# pacman -S libsodium
-```
-
-Mac OS X, using [Homebrew](https://brew.sh):
-```
-$ brew install libsodium
-$ export PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig
-```
-
-For MSYS2, see the [MSYS2](#msys2) section. There are packages available in
-the MinGW repositories for i686 and x86_64.
-
-For Visual Studio, you can download the latest available libsodium SDK from
-the [libsodium releases page](https://github.com/jedisct1/libsodium/releases/latest).
-Look for the zip file ending in `-msvc.zip`. Extract the zip file to
-`C:\sdk\libsodium`.
-
 #### protobuf
 
 If you're building on Linux or Mac, just install the appropriate packages from
@@ -231,7 +195,6 @@ a 32-bit build, install the i686 versions of these packages):
 $ pacman -S \
     git \
     mingw-w64-x86_64-gcc \
-    mingw-w64-x86_64-libsodium \
     mingw-w64-x86_64-meson \
     mingw-w64-x86_64-openssl \
     mingw-w64-x86_64-pkg-config \
@@ -265,7 +228,7 @@ C:\dev\GameNetworkingSockets> mkdir build
 C:\dev\GameNetworkingSockets> cd build
 C:\dev\GameNetworkingSockets\build> set PATH=%PATH%;C:\sdk\protobuf-amd64\bin
 C:\dev\GameNetworkingSockets\build> vcvarsall amd64
-C:\dev\GameNetworkingSockets\build> cmake -G Ninja -Dsodium_DIR=C:\sdk\libsodium ..
+C:\dev\GameNetworkingSockets\build> cmake -G Ninja ..
 C:\dev\GameNetworkingSockets\build> ninja
 ```