Testing framework setup

[RvanderLaan]

Closes #18

Set up test config, debug launch config for VSCode and added a simple Backend test.
The database is mocked with an in-memory implementation of the DBRepository file.

[hummingly]

Ok the only thing we're missing is continous integration that actually runs it. Any preferences?

[hummingly]

Ok, I should have read everything... Sorry for deleting the vscode folder... Still, I prefer CI over vscode as that would check on every commit from anyone and we could check for linting errors and make release drafts.

[RvanderLaan]

I don't have much experience with other CIs, is Travis alright?
It should work, just needs some more fiddling around with the config

[hummingly]

Travis is fine but windows support isn't great. Some open source projects moved away from it due to some changes but we can make this work first. An alternative could be Azure Pipeline from Microsoft. Support for all plattforms seems to exist.

[RvanderLaan]

Sounds good then, at least for now. Is it okay to merge?
I'll work on the toolbar #29 next if you haven't started already

[hummingly]

This is really odd that your comment shows up so late. I'm trying to add automated builds and afterwards I can merge this and #23.
You can start working on the toolbar. You only need to add a row to the grid. Do you need for this the icons? If not I could look into the custom icon branch and see what's left.

[RvanderLaan]

Alright, nice! I was just finishing that one up, it still requires one more design iteration since the icons are are a bit too big and can't be scaled down without some hacks