Improve quality with unit testing

• cover calculating of the tip view position with unit testing;
• customization of the dim color;

Small optimizations

• fix package name
• remove "withBackground()" and "withText()" from the ButtonTip.Builder - as anyway user pass the tip view. You can customize it according to your wishes and there is no need to make it inside the library. And great news: now I do not limit the tip view to TextView instance. Maybe it would be useful for somebody to use arrow image as a tip, etc.

First initial release

#The first initial release included:

• ability to construct a queue of tooltips
• tips view customizing
• support for animations of appearing and disappearing tip views. Include fade in/out animation as example