feat(brew) Update pow brew formula to install pow 0.4.3
docs(readme) Show how to enable xip.io support
Merge pull request #8 from platanus/pow-0.4.3

Updates pow to  0.4.3
Merge pull request #9 from platanus/xip-support

Adds documentation example to show how to enable xip.io support
fix(nginx) Sets X-Forwared-Host header to fix omniauth redirect mismatch