Swift 4 migration

[SebastianOsinski]

TODO:

• [x] Automatic migration + manual fixes to make app compile
• [x] Fix bug which causes navbar's title to go left after couple of pushes and pops
• [x] Update dependencies?
• [x] Update contact screen for iPhone X.

[karolus]

Maybe we could split work included in this PR, into few smaller ones? I could work separately on iPhone X fixes, while you're finishing Swift 4 migration.

[SebastianOsinski]

@karolus Good idea. @m-chojnacki Could you create swift4 branch and I'll make it target branch for this PR? We'll make our PRs to that branch (after merging this PR, as we should start from it), and after fixing everything, you'll merge that to develop? I removed some TODOs from this PR and we'll move them to other PRs

[karolus]

@SebastianOsinski You mean iPhone X fixes should be done after swift 4 migration? We could do that, but that's probably not necessary (but might reduce conflicts, though...).

[SebastianOsinski]

@karolus Yes. This PR is basically ready after stripping iPhone X related work and this one bug with back button item. So IMO it can serve as starting point for other work

[karolus]

@SebastianOsinski ok, let's do it in that order!

[m-chojnacki]

@SebastianOsinski Is it ready to go? If it is, I can merge it tomorrow to develop, then merge @karolus PR, and migrate our CI to Xcode 9

[SebastianOsinski]

@m-chojnacki It compiles, but there are still some bugs. If you are ok to have buggy version go a while on develop then we can merge it. Otherwise we could merge it to separate branch and then merge that branch after fixing all things

[m-chojnacki]

@SebastianOsinski I think we can merge it to develop despite having some bugs. We still have a "master" branch with stable version, and merging it to develop would make further development easier

[SebastianOsinski]

@m-chojnacki :thumbsup: