Add README.md for Github landing page
Add README.md for Github landing page

Change-Id: Ic299ec576f78f8d55312068a128cfb292dfdb294
Reviewed-on: http://gerrit.cloudera.org:8080/271
Reviewed-by: Alex Leblang <56023d9d1263d2a619cc54cd174c5c77e169f6fa@cloudera.com>
Tested-by: Henry Robinson <3eca10f30041813f045165784e24b5a950a6cc7e@cloudera.com>

ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC,ibmsoe/ImpalaPPC