Added functionality to resolve Issue #19 Image Saver

[tnwei]

Resolves #19 by adding show_img and save_img as class methods.

Description

• Added show_img and save_img as class methods under species.Specie, removed show_image from helpers
• Incorporated resize upon show/save.
• Uses PIL instead of matplotlib, which happens to be one of matplotlib's dependencies
• Update to examples in docs + update to README and setup.py

Motivation and Context

#19

How Has This Been Tested?

Verified to work via manual testing.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.