Implement now card

Conflicts:
	index.html
Implement Coming up and Now cards
Simplify logic for happening now
Auto size now card with tweets

Conflicts:
	css/screen.css
resize now on window resize
Scroll only the events list in now card

Conflicts:
	css/screen.css
Adjusted the "Happening Now" height and added a Program button.
- Removed the original "Program" block.
- Re-ordered the blocks on the home page