Update all dependencies

Updated from

• com.android.tools.build:gradle:2.3.1 to com.android.tools.build:gradle:3.0.0
• com.jfrog.bintray.gradle:gradle-bintray-plugin:1.2 to com.jfrog.bintray.gradle:gradle-bintray-plugin:1.7.3
• com.github.dcendents:android-maven-gradle-plugin:1.4.1 to com.github.dcendents:android-maven-gradle-plugin:1.5
• com.squareup.okhttp3:okhttp:3.4.2 to com.squareup.okhttp3:okhttp:3.7.0
• compileSdkVersion 25 to compileSdkVersion 27
• buildToolsVersion 25.0.1 to buildToolsVersion 27.0.0`
• supportLibraryVersion 25.3.1 to supportLibraryVersion 27.0.0