Move .gitignore files to the repository root

Author: werediver

example/.gitignore renamed to .gitignore

@@ -1,11 +1,13 @@
 # Files and directories created by pub
 .dart_tool/
 .packages
-# Remove the following pattern if you wish to check in your lock file
+# Leave it out of source control unless your package is an application package
 pubspec.lock
 
 # Conventional directory for build outputs
 build/
 
 # Directory created by dartdoc
 doc/api/
+
+.idea/