A maximum of 200 symbols may be requested per call to Yahoo!, and
all requested will be returned in one data.frame object.getQuote returns a data frame with rows matching the number of Symbols
requested, and the columns matching the requested columns.
The what argument allows for specific data to be requested
from yahoo, using Yahoo!'s formatting string. A list and interactive
selection tool can be seen with yahooQF.
standardQuote currently only applied to Yahoo! data, and returns
an object of class quoteFormat, for use within the getQuote function.