Comprehensive spelling/typo fixes.

Thanks to Josh Soref for generating these fixes.
diff --git a/contrib/MacOSX-launchd/launchd-README.txt b/contrib/MacOSX-launchd/launchd-README.txt
index 4783221..cf245ff 100644
--- a/contrib/MacOSX-launchd/launchd-README.txt
+++ b/contrib/MacOSX-launchd/launchd-README.txt
@@ -22,7 +22,7 @@
 
 Optionally, edit your dnsmasq configuration file to your liking.
 
-To start the launchd job, which starts dnsmaq, reboot or use the command:
+To start the launchd job, which starts dnsmasq, reboot or use the command:
 sudo launchctl load /Library/LaunchDaemons/uk.org.thekelleys.dnsmasq.plist
 
 To stop the launchd job, which stops dnsmasq, use the command: