Add The Blue Alliance links to 2001 and 2002 history pages.
Fix headings on Mentors page.
Use Markdown for 404 page.

GitHub Pages supports generated 404 pages now. Thank goodness.
Merge branch 'kevinwang-404-page-markdown'
Merge pull request #82 from kevinwang/fix-mentors-page-headings

Fix headings on Mentors page.
Merge pull request #81 from kevinwang/add-tba-years

Add The Blue Alliance links to 2001 and 2002 history pages.