Travis improvements

[snowch]

Some potential enhancements:

• provide instructions for other users to use travis with their cluster's (e.g. in a forked repo) with their own encrypted connection.properties and certificate files
• provide manual override for tests (e.g. don't run federation if that isn't configured) - maybe using a travis variable in .travis.yml (e.g. TRAVIS_SKIP_TESTS=test1,test2)

[snowch]

The second improvement has been implemented. See the TESTS_TO_SKIP variable in .travis.yml.

[pregazzoni]

BTW fix issue with TEST_SKIP not being set when running outside of TRAVIS.

I also added code to disable/enable tasks if properties are not set. This is useful if you did not set all the properties e.g for cloudant or elastic_search. The project still runs but won't fail.

You will see in the build output following.

:compileJava UP-TO-DATE
:processResources UP-TO-DATE
:classes UP-TO-DATE
:SetupLibs
:ExamplePull SKIPPED

BUILD SUCCESSFUL

Total time: 1.131 secs

Ideally it would be nice to even show that test was skipped from top build.

Test skipped  ElasticsearchIntegrationWithSpark::ExamplePull

[snowch]

thanks @pregazzoni