Use C++17 (#579)

* Use C++17

* Replace std::random_shuffle with std::shuffle

* Add random include

CMakeLists.txt

@@ -29,12 +29,12 @@ if (${CMAKE_SYSTEM_NAME} STREQUAL "OpenBSD")
   set(OPENBSD ON)
 endif()
 
-set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 list(APPEND COMPILE_OPTIONS
   $<$<COMPILE_LANGUAGE:C>:--std=c99>
-  $<$<COMPILE_LANGUAGE:CXX>:--std=c++11>
+  $<$<COMPILE_LANGUAGE:CXX>:--std=c++17>
   -U__STRICT_ANSI__
   -Wall
   -Wextra
@@ -375,7 +375,7 @@ endif(USE_BUNDLE AND NOT USE_BUNDLE_DIR)
 # Check that we have sqlite3 with FTS5
 
 if(NOT CMAKE_CROSSCOMPILING)
-  set(CMAKE_REQUIRED_FLAGS "--std=c++11")
+  set(CMAKE_REQUIRED_FLAGS "--std=c++17")
   set(CMAKE_REQUIRED_LIBRARIES ${QtCore_LIBRARIES} ${QtSql_LIBRARIES})
   check_cxx_source_runs("
     #include <QSqlDatabase>