refactoring for changing name
added ui logic, fixes bugs

connect ui and calc logic.
Fixes some bugs which did not calculate after equal
function.
e.g.
 1.   1 + 2 = 3
 2.   3 + 1 = 4
Above 2 logic was added. Before that, continuous calculation
logic couldn't be solved that operation.
Fix some bug for plus

fix to support following calculation

 5 + 1 = 6
 3 + 2 = 5

And double value usage is added in data class.
fix non terminating error in division

set limit dibit number. ROUND DONW is currently
added.
Fix 0 division error crash.

When 0 division occurs, the error is caught and
error is displied on the screen.
Fix for reset with clear button

when clear button is pressed, all calc data will be initialized
and the screen will have the charactor 0.
Add arithmetic point

set arithmetic point as String and it is added
with number as String data.
set ui weight value

each button is configured to be displied with
equal interval.
Add 00 input

When push 00 button, 00 value is added.
Fo example, when user inputs 1 and pushes 00 button,
100 is inputted to calculator.
UI is fixed to portrait

activity in AndroidManifest.xml is configured
with portrait mode.