Prepare align by adding `label` to table and crawl entities based on `ontology class`.

I added labels in order to align graphs easier.
`tvtropes` uses name as plain text in English, so I decided to use English label.

In addition, I started to crawl entities which are belong to `ontology class`, such as `Artist`, `Film` ... and so on.
There's some reason with its ontology expression.

There are many properties with classes, and I wanted to match ontology property name with sqlalchemy entities' property name even though it is written in camelcase.


DBpedia ontology:
dbpedia-owl:Artist   ->   dbpedia-owl:notableWork

SQLalchemy:
class Artist    ->   notableWork