feature/zero at decrease nominal

[swarawan]

Base idea:
On making library, we need to let user choose they needs, and strict minimum value to one instead of zero is not a good idea, because we don't know what user needs for this library. This library is simple but perfect. But lack of user needs if they want to decrease to zero or even minus value.

So my PR is about to:

• change default value to zero instead of one.
• support minus value by using setMinus(boolean) method. Default is false
• add more margin on value view to prevent cut text if counted to hundred and more
• update SDK Build for future sake