Add library to a package manager

[PatMyron]

To simply add something like:

compile 'cn.refactor.library.WavyLineView:1.0.0'

to app/build.gradle in

dependencies { }

would simplify onboarding and help adoption.

JCenter and MavenCentral are both popular package managers for Android; ~~JCenter is the default when creating a new Android project, so that'd probably be the best choice.~~