Update integrated assignment

[malachig]

Make sure the integrated assignment works as described and "makes sense".

Integrated assignment
https://rnabio.org/module-08-appendix/0008/06/01/Integrated_Assignment/

Answers
https://rnabio.org/module-08-appendix/0008/07/01/Integrated_Assignment_Answers/

Known issues:

• The answers become less complete and detailed as you get further into the assignment. Update this. e.g. complete the R code to create the visuals.
• Add some "hints" to the assignment page
• Due to limited time to complete the exercise, perhaps avoid open ended questions (What plots can you generate to help you visualize this gene expression profile?) and be more specific.
• Update the answers section to include some figures of expected results particularly where they are asked to create plots.

[obigriffith]

I think suggested overhaul has been completed with the one exception that figures of expected results have not been integrated.