Expose return dependency to user (#75)

If environment (android) doesn't provide future, expose ours to be used.

Author: ferhatelmas

build.gradle

@@ -22,13 +22,14 @@ dependencies {
 
     implementation 'com.google.guava:guava:20.0'
     implementation 'com.squareup.okhttp3:okhttp:3.11.0'
-    implementation 'net.sourceforge.streamsupport:streamsupport:1.7.0'
-    implementation 'net.sourceforge.streamsupport:streamsupport-cfuture:1.7.0'
     implementation 'com.fasterxml.jackson.core:jackson-core:2.9.6'
     implementation 'com.fasterxml.jackson.core:jackson-core:2.9.6'
     implementation 'com.fasterxml.jackson.core:jackson-annotations:2.9.6'
     implementation 'com.fasterxml.jackson.core:jackson-databind:2.9.6'
     implementation 'com.auth0:java-jwt:3.4.0'
+
+    api 'net.sourceforge.streamsupport:streamsupport:1.7.0'
+    api 'net.sourceforge.streamsupport:streamsupport-cfuture:1.7.0'
 }
 
 retrolambda {