UI improvements on landing page.

[scriptbae]

This commit introduces semantic Bootstrap support on the landing page. It's un-themed so far and preserves the simple design of the previous page.

This work contributes to the ongoing progress of #12.

[scriptbae]

Now updated with fixes for:

• 12

• 39

• 43 (partial)

• 54

• 55

• 56

  (As of 90f9c4d).

[inspectorG4dget]

PR was tested at my desk on @verandaguy's computer. All PR'd features seem to work