Update build deps (#151)

Summary:
Update some build dependencies (gradle, android plugin) and make some
minor cleanups in the gradle files along the way.
Pull Request resolved: https://github.com/facebook/Sonar/pull/151

Reviewed By: priteshrnandgaonkar

Differential Revision: D8818841

Pulled By: passy

fbshipit-source-id: 78b6592dbf967553aadead57a60023a0b5ae79b6

settings.gradle

@@ -7,8 +7,6 @@
  * in the user guide at https://docs.gradle.org/4.7/userguide/multi_project_builds.html
  */
 
-rootProject.name = 'sonar-kit'
-
 include ':android'
 include ':folly'
 include ':fbjni'