ADT #1844909: SDK manager, define XML schemas & sample XMLs

For reference, there's an XSD primer here:
- http://www.w3.org/TR/xmlschema-0/#NS
- http://www.w3schools.com/Schema/
diff --git a/.gitignore b/.gitignore
index f4c6af0..452fd81 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 *~
+*.bak
 *.pyc
 Thumbs.db