TrackerDecorator: remove the "(boxed)" annotation

That annotation does not exist, g-i is smart enough to
see by itself that TrackerDecoratorInfo is a boxed type.
TrackerPriorityQueue: Add node-based API

This exposes the fact that it is implemented using a GList, but
makes possible to remove a node without iterating the whole queue.
Those new API will be used in upcoming commits.
tracker-extract: Fix TrackerConfig not handling change notification

https://bugzilla.gnome.org/show_bug.cgi?id=719802
TrackerExtractDecorator: Fix pause/resume

It should not get the next file when the miner is paused/stopped,
or if there are no items available anymore.

This also ensure we never have more than MAX_EXTRACTING_FILES
(currently one) extraction operation running in parallel.

https://bugzilla.gnome.org/show_bug.cgi?id=719802
TrackerExtractDecorator: Add priority dbus interface

That dbus interface lets application tell tracker-extract which
rdf:type must be extracted in priority. For example, when the user
interacts with the music player, they want to give the priority to
"nfo:Audio" files.

This commit only introduces the DBus machinary, not the actual
implementation.

https://bugzilla.gnome.org/show_bug.cgi?id=719802
TrackerDecorator: Query the rdf:type for each element in the queue

The type will be used in upcoming commits to sort the elem_queue by
priority.

https://bugzilla.gnome.org/show_bug.cgi?id=719802
TrackerDecorator: Replace the elements GQueue with a TrackerPriorityQueue

This will allow more fine grained priorities than the current
append/prepend.
TrackerDecorator: Sort elem_queue to extract important files first

There are 2 things affecting an element position in the queue:
prepend (typically files from an USB key the user plugged),
and prior (the file type matches what applications needs first, e.g.
nfo:Audio).

The queue is sorted like that:
1) prepend and prior files
2) prior files
3) prepend files
4) the rest

This garantees that if I open the Music app and plug an USB key, I'll
get the MP3s from that key first, which is probably want the user
wants.

https://bugzilla.gnome.org/show_bug.cgi?id=719802

Conflicts:
	src/libtracker-miner/tracker-decorator.c
TrackerExtractDecorator: Add ClearRdfTypes DBus method

Also handle SetRdfTypes with empty strv the same as ClearRdfTypes.

https://bugzilla.gnome.org/show_bug.cgi?id=719802
tracker-extract: add "wait-for-miner-fs" setting

https://bugzilla.gnome.org/show_bug.cgi?id=719802
Add TrackerExtractController to pause/resume the miner

It listen to "wait-for-miner-fs" option and check the status
of tracker-miner-fs to pause/resume the extractor.

https://bugzilla.gnome.org/show_bug.cgi?id=719802
TrackerDecorator: Query the type of removed elements

When "?urn nie:dataSource tracker:extractor-data-source" gets removed
it means that we have to re-extract that file. It should not happen
in normal usage, only for testing purpose. In that case we have
to query its type.
TrackerExtractController: Avoid useless string comparaison
TrackerExtractController: Fix coding style
TrackerExtractDecorator: Remove useless goto.
TrackerDecorator: Add writable "priority-rdf-types" property