Earnings and ETF country functions

NEW earnings function for accessing quarterly EPS, EPS estimate, revenue and revenue estimate data.

NEW etfCountries function for accessing ETF country exposure data.

CHANGE to etfSectors function to output decimal percentage, i.e. 0.02 = 2%, rather than whole percentage, i.e. 2 = 2%.

Bug fix for historical market capitalisation data.

Addition of new assets.