Added support for Android10 dark mode.
1. Text-to-speech voice function
You can prevent mistakes by hearing the voice
2. Undo function
Each time you press the back space button, you can go back to the past input.
You can also go back to past inputs after the calculation, so we can respond flexibly to typing mistakes.
3. Mutilingual - number format
It corresponds to the difference in the digital format of each country.
(example)
1,234,567.89 Japan
1 234 567,89 France
1.234.567,89 Germany
1'234'567.89 Switzerland
4. Mutilingual - speech
This application uses Google's TextToSpeech (TTS) feature, so it can use multiple languages.
