[Tracker] libraptor as mandatory dependency

[Ivan Frade <ivan frade nokia com>]

Hi all,

 We (mainly philip and me) have been working in two new functionalities
for tracker:

1) Save the metadata of the memory cards in the memory card itself to
share between computers.
2) Backup and restore the metadata set by the user between reindexes.

 Both features requires libraptor to work (it is a parser/serializer for
turtle and other rdf formats). At the moment it is an optional
dependency but:

1) We have a lot of code between ugly #ifdefs
2) The functionality is important and make no sense to do it optional

 So i would like to propose libraptor as a mandatory dependency. Any
problem with that?

 Thanks,

Ivan