GCI-35 - Sign in page

Worked on "Sign in page"
JIRA issue: https://issues.openmrs.org/browse/GCI-35
Melange task:
https://www.google-melange.com/gci/task/view/google/gci2014/4619183002222592
Could you remove the extra padding here? I think it will help the panel content look more "balanced"