Remove unused variable to make the project cleaner.

change the formatter of log.

To use slf4j, we should insert {} into the formatter string.

new feature: PatternProcessor

Modify the log levels of LocalDuplicatedRemovedScheduler.java

The old version will print a debug level log each time the push method is
called. So sometimes, when a html page have multiple links for the same
page, the debug log will appears more than once. Also, when we meet a
duplicate URL, it will also print a log, which will be confusing.
I change the level of it to trace. And each time a URL is really push into
queue, print a debug level log.

Bugfix: Parsing error when separate chars in quotes cause in xsoup #77