Update .gitignore file to include metadata and readme-type files

New entries:

- .google/ - Metadata files
- CONTRIBUTING.md - GitHub contributor guidelines
- LICENSE - Open source license information
- README.md - Introduction to sample

Change-Id: Ib46341f5f20b5238923f784939f95c54f6dc2f12
diff --git a/.gitignore b/.gitignore
index 1756af8..9565aff 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,18 +9,21 @@
 *.class
 
 # generated files
+.google/
 bin/
 out/
 src/common
 src/template
 _index.jd
+CONTRIBUTING.md
+LICENSE
+README.md
 README-wear.txt
 
 # Libraries used by the app
 # Can explicitly add if we want, but shouldn't do so blindly.  Licenses, bloat, etc.
 /libs
 
-
 # Build stuff (auto-generated by android update project ...)
 ant.properties
 local.properties