[Fix](attempt) - Jitpack core:common error

Reference: https://stackoverflow.com/a/50563942

[2.0] First lib + demo release

* Updated README with demo app links
* Updated launcher icons (adaptive + legacy icons)
* Removed unused gradle plugin

update step status

update

update README.md

update minSdkVersion

fix list.size() = 0 bug

fix size=0 bug

update

set VerticalStepViewIndicator linePadding proportion