Improve TravisCI configurations.

Author: macedoj

.travis.yml

@@ -1,5 +1,5 @@
 language: java
-install: true
+dist: trusty
 sudo: required
 
 jdk:
@@ -18,14 +18,4 @@ before_script:
 script:
  - ./gradlew clean build --stacktrace
  - ./gradlew jacocoTestReport
- - sonar-scanner -Dsonar.verbose=true -X
-
-before_cache:
- - rm -f $HOME/.gradle/caches/modules-2/modules-2.lock
- - rm -fr $HOME/.gradle/caches/*/plugin-resolution/
-
-cache:
- directories:
- - $HOME/.gradle/caches/
- - $HOME/.gradle/wrapper/
- - $HOME/.m2
+ - sonar-scanner -Dsonar.verbose=true -X