Add Carthage support

[tbaranes]

This PRs changed a lot of small things, but doesn't touch the code at all. So, to add Carthage support here what it changes:

• New ISHLogDNA.Ixcworkspace which is containing:
  • ISHLogDNA.xcodeproj which has one shared scheme ISHLogDNA generating a ISHLogDNA.framework
  • ISHLogDNA Example.xcodeproj which contains the two sample apps

Following this, I have changed a bit the sources files organisation. Here a few screens:

I have one test failing, but still have to check if it's new or was already failing before.

[tbaranes]

Closing, now it's time for SPM