New propagation, including N-1 splitters and mergers and locking, mostly done

[Borimino]

Has a mysterious compile-error:

'std::unique_ptr<MetaPin,std::default_delete>::unique_ptr(const std::unique_ptr<MetaPin,std::default_delete> &)': attempting to reference a deleted function

Also still lacks GUI regarding "Locked" pins.

[adepierre]

Hello thank you for the PR. Unfortunately, this has many changes in many files for multiple features at the same time. I am currently in vacation and won't probably have enough time to review it in details before at least next week.

From a quick look though, I can see that there are some inconsistencies in code style (tab instead of space, std::cout in the code etc...)