Middleman 3.0 compatibilty.

- Moved some redirects into the rack middleware
- mm 3.0 extension API
- TODO: page '/post/*', :proxy => '/index.html' isn't working right now
Hacky way of supporting permalink urls in mm 3.0
Doc & example updates for middleman 3.0 support
Merge branch 'mm-3'

* mm-3:
  Doc & example updates for middleman 3.0 support
  Hacky way of supporting permalink urls in mm 3.0
  Middleman 3.0 compatibilty.
Move blocks module into own file
Make the linter happy :)
Add some tests for permalink page behavior
Version bump to 0.2.0
Regenerate gemspec for version 0.2.0