Write basic test for Core

[sudden6]

The test should run at TravisCI and at least include:

• startup without proxy
• startup with invalid proxy
• loading of unencrypted save file
• loading of encrypted save file
• try loading a broken save file
• saving a save file

More tests and ideas welcome

[zetok]

• create profile
• delete profile
• encrypt profile
• decrypt profile
• rename profile
• delete history
• change password and check if new one works

[sudden6]

@zetok these are all operations that happen outside the Core module. The core module is only the wrapper around toxcore.

I think this would fit better in a new issue.

[zetok]

Oh, I see, I thought it was about core functionality.

[sudden6]

Basic tests for Core have been implemented here: https://github.com/qTox/qTox/blob/master/test/core/core_test.cpp