added javascript for .findOne() and .find() quizzes
added document for comparison query operators
added document to explain inequality query  operators
added document to explain $regex. $type and $exists
explain $and and $or query  operators
explain queries inside arrays
$all and $in referred to arrays
queries in sub-documents
examples for cursors
samples for count
wholesale updates and $set/$inc
update Quiz format
updates in arrays
multi-document updates
samples for document deletion
populate document with values
add arrays to document
add subdocuments
add Quiz for representation
samples for insertions