Implement loading inherited attributes

- The attribute value is got from current node OR from the closest parent
  node which contains not-null/non-empty value
- Refactor getting inherited route values to remove several hard-coded
  strings and prevent copy-paste
Add config property to setup custom inherited attributes
Update .gitignore
Remove MvcMusicStore project

- The website will be replaced with unit tests and a separate demo web
  site
Add Unit test project
Add packages folder to repository
Remove .Net 3.5 conditional system.web.mvc ref

- From now only .net 4.0+ is supported