Force clang tidy results to be colourful

ci/clang-tidy.sh

@@ -11,4 +11,4 @@ echo -e "\033[0;34mRunning clang-tidy...\033[0m"
 
 cd "$(dirname "$0")"
 clang-tidy-4.0 `find ../src/ -type f -regextype posix-egrep -regex '.*\.(cpp|hpp|c|h)'` \
-    -- -std=c++14 -I../inc
+    -- -std=c++14 -I../inc -fcolor-diagnostics