Added cmakelists and changed externals file structure

CMakeLists.txt

@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.1)
+
+# C++ 11 is standard
+set(CMAKE_CXX_STANDARD 11 CACHE STRING "The C++ standard to use")
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
+project(
+    ProjectEuler
+    VERSION 0.0.1
+    LANGUAGES CXX
+)
+
+add_executable(base base.cpp)
+
+# For each euler problem a new executable here
+add_executable(euler059 059/main.cpp)