Cleanup. (#132)

- Split the large CMakeList.
- Remove travis
- Remove gitlab-ci.yml

cmake/ftxui_install.cmake

@@ -0,0 +1,29 @@
+include(GNUInstallDirs)
+install(TARGETS screen dom component
+    EXPORT ftxui-export
+    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}/ftxui/
+    ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}/ftxui/
+)
+
+install(DIRECTORY include/ftxui DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+
+include(CMakePackageConfigHelpers)
+configure_package_config_file(ftxui-config.cmake.in
+  ${CMAKE_CURRENT_BINARY_DIR}/ftxui-config.cmake
+  INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/ftxui/cmake
+  PATH_VARS CMAKE_INSTALL_INCLUDEDIR
+)
+write_basic_package_version_file(
+  ftxui-config-version.cmake
+  VERSION ${PACKAGE_VERSION}
+  COMPATIBILITY AnyNewerVersion
+)
+
+install(FILES ${CMAKE_CURRENT_BINARY_DIR}/ftxui-config.cmake
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/ftxui
+)
+install(EXPORT ftxui-export
+  FILE ftxui-config-version.cmake
+  NAMESPACE ftxui::
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/ftxui
+)