Remove one level of nesting; add README.txt

thirdparty/nlohmann_json/CMakeLists.txt

@@ -1,7 +1,7 @@
 add_library( nlohmann_json INTERFACE )
 
-target_include_directories( nlohmann_json INTERFACE include )
+target_include_directories( nlohmann_json INTERFACE ${CMAKE_CURRENT_SOURCE_DIR} )
 
 target_sources( nlohmann_json INTERFACE 
-    ${CMAKE_CURRENT_SOURCE_DIR}/include/nlohmann/json.hpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/nlohmann/json.hpp
     )

thirdparty/nlohmann_json/LICENSE.MIT

@@ -0,0 +1,17 @@
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

thirdparty/nlohmann_json/README.txt

@@ -0,0 +1,4 @@
+This directory contains the nlohmann/json project from https://github.com/nlohmann/json.
+
+It is licensed under MIT, with the license text in this directory.
+