Add keystore.gradle file

Update the .gitignore file in the library module
Update kotlin version
Move bintray and maven plugin versions to dependencies.gradle

build.gradle

@@ -10,8 +10,8 @@ buildscript {
     dependencies {
         classpath "com.android.tools.build:gradle:$versions.gradlePlugin"
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$versions.kotlin"
-        classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.7.3'
-        classpath 'com.github.dcendents:android-maven-gradle-plugin:1.4.1'
+        classpath "com.jfrog.bintray.gradle:gradle-bintray-plugin:$versions.bintrayPlugin"
+        classpath "com.github.dcendents:android-maven-gradle-plugin:$versions.mavenPlugin"
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
     }

dependencies.gradle

@@ -4,10 +4,12 @@ ext.versions = [
         buildTools        : '26.0.2',
         publishVersion    : '0.0.1',
         publishVersionCode: 1,
-        gradlePlugin      : '3.0.0',
+        gradlePlugin      : '3.0.1',
+        bintrayPlugin     : '1.7.3',
+        mavenPlugin       : '1.4.1',
 
         supportLib        : '27.0.0',
         espresso          : '3.0.1',
-        kotlin            : '1.1.51',
+        kotlin            : '1.2.0',
         leakCanary        : '1.5.4'
 ]

library/.gitignore

@@ -1,2 +1 @@
-/build
-keystore.gradle
+/build

library/keystore.gradle

@@ -0,0 +1,3 @@
+ext {
+    bintray_key = ""
+}