First tool for the Region of Interest (ROI) module in Sunpy

This is to start to move the ball into the ROI object in sunpy (https://github.com/sunpy/sunpy/issues/164)
These files allows to convert chaincode into coordinates for visualization and other operations on images, but in principle applicable to other data formats like radio spectra.
Chaincodes are produced by the HELIO Feature Catalogue and by the Heliophysics Event Knowledgbase to describe the contour of the features observed. 
I've implemented it using the HELIO definition, though it could be possible that HEK defined the chaincode in a different way.
This image shows how HELIO uses it and how's implemented in here:

![shapenumber1](https://f.cloud.github.com/assets/963242/66181/f18561d6-5e9a-11e2-9fc0-baab79929831.gif)

Tests also included (at least the ones used for the development as this was done using TDD)

All the tests are successful in 2.7 and I don't foresee any incompatibility with python 3.