moved json library to extern

cf16f22e · Sebastian Eibl · 66f08038 · cf16f22e · 6d4eed5a · 66f08038
Commit cf16f22e authored 4 years ago by Sebastian Eibl
--- a/.gitmodules
+++ b/.gitmodules
@@ -7,3 +7,6 @@
 [submodule "extern/exprtk"]
 	path = extern/exprtk
 	url = https://github.com/ArashPartow/exprtk.git
+[submodule "extern/json"]
+	path = extern/json
+	url = https://github.com/nlohmann/json.git
--- a/json @ 6d4eed5a
+++ b/json @ 6d4eed5a
+Subproject commit 6d4eed5aeb59a3f40831edacf8693e53a543e832
--- a/src/core/extern/json.hpp
+++ b/src/core/extern/json.hpp