CLEANUP: Update .gitignore

This excludes the currently tracked files from being ignored.
diff --git a/.gitignore b/.gitignore
index 7e45489..3a760af 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,7 +2,11 @@
 # than blocking about 500 different test files and bug report outputs.
 /.*
 /*
+!/.cirrus.yml
+!/.gitattributes
+!/.github
 !/.gitignore
+!/.travis.yml
 !/CHANGELOG
 !/LICENSE
 !/BRANCHES