update travis

Author: DBarthe

.travis.yml

@@ -1,11 +1,19 @@
 language: java
 jdk:
   - oraclejdk8
+
+addons:
+  apt:
+    packages:
+      - oracle-java8-installer
+env:
+  global:
+    - GRADLE_OPTS="-Xms128m"
+
 before_install:
   - chmod +x gradlew
-  - export JAVA_OPTS="-Xmx2048m -XX:MaxPermSize=386m"
 
-install: "./gradlew distZip"
+install: ./gradlew assemble distZip -Pskip.signing
 
 deploy:
   provider: releases