Better handling of IN queries in the query builder.

Now you can pass an array of values to the query builder when specifying an "IN" operator. Automatically escapes quotes and puts it in the correct format.

Example:

```ruby
numbers = %w(1234 4321 5678 8765)
util = Quickbooks::Util::QueryBuilder.new
clause = util.clause("DocNumber", "IN", numbers)
query = "SELECT * FROM Invoice WHERE #{clause}"

# query
# SELECT * FROM Invoice WHERE DocNumber IN ('1234', '4321', '5678', '8765')
```

With passing test that also checks for single quotes.