Replace Eigen3 with TNL in the build configuration

.gitmodules

-[submodule "dep/eigen"]
-	path = dep/eigen
-	url = https://github.com/eigenteam/eigen-git-mirror.git
 [submodule "dep/Catch2"]
 	path = dep/Catch2
 	url = https://github.com/catchorg/Catch2.git
+[submodule "dep/tnl"]
+	path = dep/tnl
+	url = https://mmg-gitlab.fjfi.cvut.cz/gitlab/tnl/tnl-dev.git

CMakeLists.txt

-# CMakeLists.txt
-#
-#     Author: Fabian Meyer
-# Created On: 12 Jul 2019
-
-cmake_minimum_required(VERSION 3.5)
+cmake_minimum_required(VERSION 3.13)
 project(gdcpp)
 
-SET(CMAKE_CXX_STANDARD 11)
+SET(CMAKE_CXX_STANDARD 14)
 SET(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 if(CMAKE_COMPILER_IS_GNUCXX)
     set(CMAKE_CXX_FLAGS "-Wall -Wextra")
 endif(CMAKE_COMPILER_IS_GNUCXX)
 
+# force colorized output in continuous integration
+if( DEFINED ENV{CI_JOB_NAME} OR ${CMAKE_GENERATOR} STREQUAL "Ninja" )
+   message(STATUS "Continuous integration or Ninja detected -- forcing compilers to produce colorized output.")
+   if( CMAKE_CXX_COMPILER_ID STREQUAL "Clang" )
+      set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fcolor-diagnostics" )
+   elseif( CMAKE_CXX_COMPILER_ID STREQUAL "GNU" )
+      set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fdiagnostics-color" )
+   endif()
+endif()
+
 # find OpenMP
 find_package(OpenMP)
 if(OPENMP_FOUND)
@@ -21,12 +26,11 @@ if(OPENMP_FOUND)
     set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${OpenMP_EXE_LINKER_FLAGS}")
 endif(OPENMP_FOUND)
 
-# find_package(Eigen3 REQUIRED)
 add_subdirectory(dep)
 
 include_directories(
     include
-    ${EIGEN3_INCLUDE_DIR}
+    ${TNL_INCLUDE_DIR}
 )
 
 install(FILES "include/gdcpp.h"

dep/CMakeLists.txt

-# CMakeLists.txt
-#
-#     Author: Fabian Meyer
-# Created On: 12 Jul 2019
-
-set(EIGEN3_ROOT "${CMAKE_CURRENT_LIST_DIR}/eigen" CACHE INTERNAL "")
-set(EIGEN3_INCLUDE_DIR "${EIGEN3_ROOT}" CACHE INTERNAL "")
+set(TNL_ROOT "${CMAKE_CURRENT_LIST_DIR}/tnl" CACHE INTERNAL "")
+set(TNL_INCLUDE_DIR "${TNL_ROOT}/src/TNL" CACHE INTERNAL "")
 
 set(CATCH2_ROOT "${CMAKE_CURRENT_LIST_DIR}/Catch2" CACHE INTERNAL "")
 set(CATCH2_INCLUDE_DIR "${CATCH2_ROOT}/single_include" CACHE INTERNAL "")

eigen @ a1b9c26c

-Subproject commit a1b9c26c5e62cb8c17836e601edd64b92aa8e5ae

tnl @ 91a599f3

+Subproject commit 91a599f303ac734757625875bdacad7f10b07083