Setup zulip server and install android sdk to run tests on travis.

[Sam1301]

This pr addresses #271 Since dist trusty is not compatible with android on travis we need to install android sdk and other support libraries manually in order to make use of trusty to run zulip dev environment.

The existing tests are flaked (verified by me and kunal) so they have been commented out for now.

[smarx]

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[timabbott]

@saketkumar95 @kunall17 @vishwesh3 can you give this a review?

[yadav-rahul]

@timabbott I can do it too if you agree.

[saketkumar]

@yadav-rahul Yeah sure do it. :+1:

[yadav-rahul]

@saketkumar95 Thanks for your concern. Waiting for @timabbott reiview. :)

[timabbott]

@yadav-rahul you don't need my permission to do a code review; just review it and post your feedback :)

[yadav-rahul]

@timabbott OK :)

[kunall17]

@timabbott This won't work now because the espresso test's are flaky and they work sometimes and sometimes don't! https://github.com/zulip/zulip-android/issues/342

So we need to have some test's for the travis to run!

[timabbott]

Well we can do the infrastructure setup for Travis CI to be able to run a single do-nothing test with the app built, and get that debugged, while in parallel folks work on #342. So I think this is still useful to work on.

[zulipbot]

@Sam1301, your pull request has developed a merge conflict! Please review the most recent commit (f791888) for conflicting changes and resolve your pull request's merge conflicts.