Version 2.2 is now up on Google Play. This adds a new Number Format setting (under General). This allows the user to choose the decimal mark, digit grouping, and function argument separator that they wish to use. Previously the decimal mark was always a point and there was no digit grouping. When digit grouping is turned on, digits are automatically grouped as you enter them (unless you have basic text entry enabled). For example, if you set the digit grouping to a comma and enter "12345", it will automatically be grouped and display "12,345" in the entry.
Currently the calculator history only stores the last 20 calculations in the calculator history. I have had requests for a way to permanently store calculations. For the next update I am planning on adding a way to permanently store calculations. I have some ideas on how I would like to add this feature and I think it will end up being pretty neat once I get it in. This feature will only be available in the paid version. Once I get some of it implemented I will post some screenshots with more information on how it will work.