Restore default zone/machine-type.

Use default mount options to avoid SELinux issues on reboot

Misc updates for release.

Change spark startup processes so master accquires workers on total reboot.

Update default Spark version to 1.2.1.

Update Spark driver memory settings to scale with machine size.

Make generate_config also add the necessary import_env commands for "-e"

re-add default zone/instance size

minor fixed in HDP readme

notes for HDP 1.3

simplified the thp script

Merge pull request #18 from dennishuo/master

Add TODO to make "resize" as core command, move the resize_env.sh file into extensions/google/experimental.

Add extension 'resize_env.sh' for manual resizing.

Add a var SKIP_MASTER to operate only on workers.