update epicshop, refactor <CodeFile /> usage

[kettanaito]

• Updates to the latest version of EpicShop.
• Replaces the usages of <CodeFile/> with the inlined code snippets.
• Consistently uses lines over highlight in code snippets.
• Improves the code snippets by using add and remove where appropriate to show the code that I replace as a part of the solution.

Also, removes 06/01 solution because it was outdated. I will push the up-to-date solution description later today/tomorrow.