An acceptance test for chat error handling
Added Robolectric
Introduced HttpChatTranslationTest test case that uses Robolectric
Stub error handling in HttpChatTranslation
ChatTranslation is started/stopped in fragment's onStart()/onStop() to avoid strange effects in tests
Spawned an inner class HttpChatClient
Spawned an inner class HttpChatClient
Changes in ChatTranslation interface to support error handling
Handling errors in HttpChatTranslation
Shows error message when chat translation is not available
Added tmp/ to .gitignore