Merge branch 'feature/mergeGraphs'

This simplifies the Nepomuk Storage code base and results in the fewer
graphs to be used when inserting data. This results in a much faster
Nepomuk and a more maintainable code base. (Over 300% performance games)

Unfortunately, this also means that the old data will need to be
migrated. The migration should get automatically done for everyone by
backing up their tags and ratings and restoring them. It should ideally
just take a couple of minutes.

Unfortunately, this means that everyone will have to reindex all of
their data. This is okay for files, but it's going to be a little slow
for Emails. Good Luck.

For the 4.11 release we plan to enhance the Email Indexing scheduling
code so that it isn't so CPU intensive. So, the user should not mind
that much.

CCMAIL: nepomuk@kde.org