Print out how long certain steps take to finish.

Currently, the crawler only logs how long an individual crawling takes. It should also print out how long smaller tasks take. For example:

How long to download a specific feed (some sites are slower than others).
How long to parse a specific feed (I'm assuming that most feeds take about the same amount of time).
How long to download a specific article (some sites are slower than others).
How long to parse a single article (some articles are longer than others or have ugly HTML).

gt-big-data / QDoc