Helper text color customizable.
Move bottom lines initialization from onWindowFocusChanged() to onMeasure(), in order to avoid some bugs.
introduced new strategy for the default "baseColor" and "primaryColor". New strategy:
1. The default base color is according to the current Theme's "windowBackground" attribute. If the "windowBackground" is a light color, the default base color is BLACK, otherwise the default base color is WHITE.
2. The default primary color is according to the device's OS version and the current Theme. If the OS version is LOLLIPOP or greater, the default primary color is the theme's "android:colorPrimary" attribute; or if the current Theme is AppCompat, the default primary color is the theme's "colorPrimary" attribute; otherwise the default primary color is just the base color.
Tweak: Change bottom line's normal state color to translucence.
New option: floatingLabelSpacing, to set the spacing between the main text and the floating label.
New option: minCharacters
added android:gravity attribute support for floating label.