Update jsoncpp ahd catch2 deps

- Also require C++14.

Author: ibc

CMakeLists.txt

@@ -3,11 +3,11 @@ cmake_minimum_required(VERSION 3.0)
 project(sdptransform VERSION 1.2.9)
 
 # For CMake >= 3.1.
-set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 # For CMake < 3.1.
-add_compile_options(-std=c++11)
+add_compile_options(-std=c++14)
 
 subdirs(test readme-helper)