Add header area with slidedeck for marketing

[panesofglass]

Marketing you say? Yes, such as:

• User groups
• Recently recorded presentations
• UG Content
• New OSS projects (such as those at https://github.com/fsprojects)
• Other online resources (see Add section for other online community resources #20)

Items to accomplish the above:

• Add header area (see Fix navigation #9)
• Add slidedeck script
• Add slides

[panesofglass]

Do this as part of #21