Removes Guava dependency

Author: collinsmith

core/build.gradle

@@ -26,7 +26,6 @@ dependencies {
 
 // Libraries
 dependencies {
-  api "com.google.guava:guava:20.0"
   api "com.android.support:support-annotations:28.0.0"
   api "commons-io:commons-io:2.5"
   api "org.apache.commons:commons-lang3:3.9"