Create README.md
Force line-break on post descriptions.
Addresses GitHub issues #7 and #8. Moved descriptions and captions from aside to a body container within the main content areas. Major adjustments on some areas. Refer to diff.
Addresses issue #2 but part of the committed code includes a workaround that requires accompanying documentation for it to work with the end-user (refer to diff for more info). PXs converted to EMs where applicable. Polished Tumblr control's behavior when vertically scrolling.