Migrate from Posts Bundle to Content Types bundle

refs #95
Added the missing singular_name configuration.
Default to including _$type as the path if path detection is used but path is not listed ... not sure if this makes a lot of sense.
Fixed a typo in method name.
Only do the default date based sorting if both items have a date and a title. Otherwise sort based on relative pathname.
allow for accessing meta directly in proxy source items. (hack?)
This was not supposed to be here.
Inject next and previous items
Merge pull request #96 from simensen/content-types

Migrate from Posts Bundle to Content Types bundle