Add a script to build the player for all three platforms in one go

build.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+EDITOR="$HOME/Unity/Hub/Editor/2019.1.10f1/Editor/Unity"
+BUILD_DIR="/tmp/build-unity"
+
+rm -rf "$BUILD_DIR"
+
+mkdir -p "$BUILD_DIR/Linux"
+mkdir -p "$BUILD_DIR/macOS"
+mkdir -p "$BUILD_DIR/Windows"
+
+"$EDITOR" -buildLinuxUniversalPlayer "$BUILD_DIR/Linux/SEGMent"   -projectPath "$PWD" -batchmode -quit
+"$EDITOR" -buildOSXUniversalPlayer   "$BUILD_DIR/macOS/SEGMent"   -projectPath "$PWD" -batchmode -quit 
+"$EDITOR" -buildWindows64Player      "$BUILD_DIR/Windows/SEGMent" -projectPath "$PWD" -batchmode -quit
+