CLEANUP: assorted typo fixes in the code and comments

This is 7th iteration of typo fixes
diff --git a/src/checks.c b/src/checks.c
index ee2997a..e5b5375 100644
--- a/src/checks.c
+++ b/src/checks.c
@@ -3266,7 +3266,7 @@
 
 	check->wait_list.tasklet = tasklet_new();
 	if (!check->wait_list.tasklet)
-		return "out of memroy while allocating check tasklet";
+		return "out of memory while allocating check tasklet";
 	check->wait_list.events = 0;
 	check->wait_list.tasklet->process = event_srv_chk_io;
 	check->wait_list.tasklet->context = check;