Enable automatic coding style linting with ktlint (also on CI)

This way the coding style is guaranteed to stay consistent.
diff --git a/.gitignore b/.gitignore
index 89216d5..ec60569 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,6 +9,7 @@
 lib/
 .idea/*
 !.idea/runConfigurations*
+!.idea/inspectionProfiles*
 !.idea/codeStyles*
 *.ipr
 *.iws