Add codecov support on CI.

Author: android10

.travis.yml

@@ -46,4 +46,8 @@ before_script:
 script:
  - ./gradlew clean
  - ./gradlew compileApp
- - ./gradlew runUnitTests
+ - ./gradlew runUnitTests
+ - ./gradlew runTestCoverage
+
+after_success:
+ - bash <(curl -s https://codecov.io/bash)