Renamed the 'a' directory to 'opinion' directory
Added a new article loader method

Added a new loader method to randomly load a given number of articles
from any news source. We can use it during evaluation to generate our
sample sets.
Merge remote-tracking branch 'refs/remotes/origin/master'

Conflicts:
	IR-Project/src/cs/virginia/edu/ir/news/article/mapper/Main.java