Added a generated page file so live refresh can work in development as expected.

- Added pushState setting which is needed for development work to work correctly, apparently.
- Added index.us page which is used as a layout during development, so Lineman/Grunt can handle live updates
Updated the README with known problem about pages task.

- lineman grunt pages task needs to be ran, because the Lineman's html
  layout file doesn't get generated.