Improve efficiency when querying to getQuestionsFromCardbox

[spherulitic]

The algorithm to get questions from the cardbox is:

• Query the cardbox for the questions
• If not enough questions are returned, execute makeWordsAvailable()
• Query the cardbox for questions again
• Repeat makeWordsAvailable() until enough questions are returned from the query

This is insane. The driver behind this is that makeWordsAvailable() operates in a specific increment (adding new words, pulling from backlog, etc).

However, makeWordsAvailable() should take an argument telling how many words should be made available, so we only have to run it once.