Update latest version and examples to 0.5.0

Also added direct link to the latest release page for easy downloading.

README.md

@@ -29,12 +29,12 @@ ycsb-users@yahoogroups.com
 Getting Started
 ---------------
 
-1. Download the latest release of YCSB:
+1. Download the [latest release of YCSB](https://github.com/brianfrankcooper/YCSB/releases/latest):
 
     ```sh
-    curl -O --location https://github.com/brianfrankcooper/YCSB/releases/download/0.4.0/ycsb-0.4.0.tar.gz
-    tar xfvz ycsb-0.4.0.tar.gz
-    cd ycsb-0.4.0
+    curl -O --location https://github.com/brianfrankcooper/YCSB/releases/download/0.5.0/ycsb-0.5.0.tar.gz
+    tar xfvz ycsb-0.5.0.tar.gz
+    cd ycsb-0.5.0
     ```
     
 2. Set up a database to benchmark. There is a README file under each binding