🔖 set version to 3.1.0

- updated documentation wrt. new repository layout
- temporarily switched off Homebrew --HEAD building (can only be switched on after release)
- set copyright date to 2018

test/src/unit-meta.cpp

@@ -1,11 +1,11 @@
 /*
     __ _____ _____ _____
  __|  |   __|     |   | |  JSON for Modern C++ (test suite)
-|  |  |__   |  |  | | | |  version 3.0.1
+|  |  |__   |  |  | | | |  version 3.1.0
 |_____|_____|_____|_|___|  https://github.com/nlohmann/json
 
 Licensed under the MIT License <http://opensource.org/licenses/MIT>.
-Copyright (c) 2013-2016 Niels Lohmann <http://nlohmann.me>.
+Copyright (c) 2013-2018 Niels Lohmann <http://nlohmann.me>.
 
 Permission is hereby  granted, free of charge, to any  person obtaining a copy
 of this software and associated  documentation files (the "Software"), to deal
@@ -42,10 +42,10 @@ TEST_CASE("version information")
         CHECK(j["url"] == "https://github.com/nlohmann/json");
         CHECK(j["version"] == json(
         {
-            {"string", "3.0.1"},
+            {"string", "3.1.0"},
             {"major", 3},
-            {"minor", 0},
-            {"patch", 1}
+            {"minor", 1},
+            {"patch", 0}
         }));
 
         CHECK(j.find("platform") != j.end());