Revised intro text; Experimented with new login bar.

Revised the MapScore description on the login page.

Also tried a one-line bar.  Hardhik: please test that the simple links
work like the blue buttons below them.  If so we can remove the blue
buttons and make this one-line.
Merge branch 'hardhik' of https://github.com/ctwardy/mapscore into hardhik