Create helper for creating sp_playlistcontainer_callbacks
Cleanup create_trampoline helper.

Manager has been removed from function and struct as it was never used. To
simpify use, userdata may now be NULL and will be replaced with Py_None instead.
Trampoline variable naming cleanup
Cleanup of albumbrowser.

Mainly fixes variable naming, formating and code consistency. This also kills
off an unused struct member _callback, which was only being used by an XDECREF
in the dealoc method. PyObject is now prefered to using AlbumBrowser, access
to the internal sp_albumbrowse can now be done with the AlbumBrowser_SP_ALBUMBROWSE
macro. Finally AlbumBrowser_browse_complete was upaded to match albumbrowse_complete_cb.
Correct comment spacing for AlbumBrowser_as_sequence
Minor style cleanups to albumbrowser.

Turns out whitespace in PyTypeObject inidicate if struct member is optional.
Fixed comments to reflect this. Also made some minor estetic change to the
header file.
Cleanup album code.

Again mainly formating fixes. Moves to PyObject instead of Album and use of
Album_SP_ALBUM instead of "direct" access.
Put type on one line in album.h and albumbrowse.h
Cleanup artist code.
Cleanup artistbrowse.
Cleanup image.
Cleanup link.

Also adds *_SP_* helpers for playlist, search and track.
Cleanup module.
Cleanup track.
Cleanup user.
Remove un-needed PyType_Ready calls in init helpers.
Cleanup search.
Cleanup toplistbrowser.

Ensures we call create_trampoline late enough, as otherwise we leak a ref.
Though we could still leak if creating the browser fails. Also adds a todo
to remove the incref for the browser as it should be one to high.
Revert "Remove un-needed PyType_Ready calls in init helpers."

This reverts commit 00e8d68116df72899974b2bbe7026ac2c16cdc09.
Cleanup session.

Also sneaks in fix for image id size_t casting and adds a ton of ref count
related todos.