Refactor ProjectUpAndDownloadTest

* update okhttp lib to 1.2.1
* reintegrate testRenameProjectNameAndDescriptionWhenUploading
* reintegrate testDownload
* reintegrate testUploadModifiedStandardProject
* remove unnecessary intents
* refactor private methods

Fix issue #720
Jenkins testrun: [623](https://jenkins.catrob.at/job/Catroid-Multi-Job-Custom-Branch/623/) ([345](https://jenkins.catrob.at/job/Catroid-single-UI-emulator/345/), [346](https://jenkins.catrob.at/job/Catroid-single-UI-emulator/346/))