Split tests up for easier debugging
Optional start_date / end_date
Updated README to reflect new API call
Added split API
Updated README to reference splits
Single quotes
Cleaner dividends API
Merge branch 'optional-historical-dates' into fengb
Merge branch 'splits' into fengb

Conflicts:
	test/yahoo_finance_test.rb
Merge branch 'single-quotes' into fengb
Merge branch 'dividends' into fengb

Conflicts:
	README.md