Work in progress for #316. Fixing Cookbook.pod

I've been stuck on this for a while trying to do Cookbook.pod, Tutorial.pod and Manual.pod. It was getting tedious, so with @ambs consent I will send bunch of small commits as I go to address issue #316.

In this PR I Fixed spelling and grammar issues. Fixed invalid code. Added a better code sample for sessions and logging in. Also tested about half of the code samples on OSX and CentOS.