Update Readme.md

Readme.md

+Features
+--------
+
+* dictionary of Series (dios)
+* fast as pd.DataFrame
+* every 'column' has its own index
+* use very less memory then a disalignd pd.Dataframe
+* `dios[var]` where `var` can be a list, slice, string
+* `dios[ts,var]` where `ts` can be a slice (`ts:ts`) a single timestamp, or anything pd.Series will eat
+* `+,-,*,/,//,%` and `==,!=,>,>=,<=,<` and `~,&,|,^` and `is, in` implemented
+* run **any** method from pd.Series on dios with `dios.pipe(pd.Series.method)` or `dios.foreach()` (simple alias)