fixed issue when yahoo test failes because of time offset issues (#543)

* fixed issue when yahoo test failes because of time offset issues
* updated whatsnew file for v0.7.0
* fixed lines length
* PEP8 E127 fix

Author: duch94

docs/source/whatsnew/v0.7.0.txt

@@ -69,4 +69,5 @@ Bug Fixes
 - Added back support for Yahoo! price, dividends, and splits data for stocks
 	and currency pairs (:issue:`487`).
 - Add `is_list_like` to compatibility layer to avoid failure on pandas >= 0.23 (:issue:`520`)
+- Fixed Yahoo! time offset (:issue:`487`).
 - Fix Yahoo! quote reader (:issue: `540`)

pandas_datareader/yahoo/daily.py

@@ -97,10 +97,17 @@ def get_actions(self):
     def url(self):
         return 'https://finance.yahoo.com/quote/{}/history'
 
+    # Test test_get_data_interval() crashed because of this issue, probably
+    # whole yahoo part of package wasn't
+    # working properly
     def _get_params(self, symbol):
+        # This needed because yahoo returns data shifted by 4 hours ago.
+        four_hours_in_seconds = 14400
         unix_start = int(time.mktime(self.start.timetuple()))
+        unix_start += four_hours_in_seconds
         day_end = self.end.replace(hour=23, minute=59, second=59)
         unix_end = int(time.mktime(day_end.timetuple()))
+        unix_end += four_hours_in_seconds
 
         params = {
             'period1': unix_start,