Added some code and explanation for FDR
First draft of loading images tutorial
Removed reference to nipy, I'm not using it
Merge pull request #2 from arokem/introduction

Introduction
Merge pull request #3 from matthew-brett/playing-with-images

WIP : First draft of loading images tutorial
WIP : comparing uncorrected, Bonferroni and FDR
First pass of the entire introduction.
Small fix.