Added Lazy BSON as a input type

Speeds (this is all compared with mongo-hadoop master, BSONComparator isn't
included):

enron:
    Original (mongodb/mongo-hadoop/master) - 62.63s
    lazyBSON = false (Code added, option set to false) - 65.45s
    lazyBSON = true (Code added, option set to true) - 64.13s

PageRank 1 iteration:
    Original (mongodb/mongo-hadoop/master) - 
        823779 milliseconds = 13.7296 minutes
    lazyBSON = true (Code added, option set to true) - 
        611790 milliseconds = 10.1965 minutes