The changes include:

  * adding a single-include header and deprecating
    nautilus-extension-types.h and direct inclusions of individual
    headers;

  * type definition simplifications - this causes some breakages in
    nautilus-file, because NautilusFile used to be typedefed to
    NautilusFileInfo, and that is no longer possible, so the interface
    implementation was moved to static functions and the public
    NautilusFile API provides thin wrappers for them to maintain
    compatibility;

  * documentation cleanups and reorganization;

  * general build rule and code cleanups: mostly g_auto* sprinkled
    around and style changes (sorry)