Fixed Call button crash and Gradle build fail

[Niranjan-B]

1. The ripple effect library used has an open issue (Underflow in restore - more restores than saves : on Android M (6.0) traex/RippleEffect#76). Used this (https://github.com/patrickpissurno/RippleEffect/) library to work around the problem having the same API.
2. The build was failing on Android Studio 3.1 due to differences in version numbers. The support library version number used was 27.1.1 but 'com.github.rey5137:material:1.2.1' was using 'com.android.support:cardview-v7:22.2.0 ' which created the conflict.
3. Resolved "Failed to resolve: common [duplicate]" (on Android Studio 3.1) by re-positioning the maven and google repository URL's in top level build.gradle file. FYI -> (https://stackoverflow.com/questions/50565776/build-gradle-error-failed-to-resolve-common?noredirect=1&lq=1)

[Swati4star]

The changes are good.
Just squash the commits into a single one.