Fix uninitialized variables

[visuve]

• Found them using Cppcheck

[alt3r-3go]

@visuve, looks like the bugfix part should now be removed after that "New sync wizard" piece with sizeof() bug was reverted, to also resolve the PR branch conflicts with master.

[visuve]

@alt3r-3go okay, thanks for mentioning! I will fix the uninitialized variable issues later.

Btw, can I use C++11 or greater?

[alt3r-3go]

This is not strictly codified in the docs I think, but the Linux makefile uses gnu++14 (while explicitly mentioning 17 won't work) and the macOS one uses c++11. Haven't checked the Windows setting, but in view of the above 11 should be ok, yes. @idrassi, please chime in if you have any better definition here.

[visuve]

@alt3r-3go I rebased the changes and used C++11 style initialization.

I think there is quite much to do to modernize the code base to C++11 (or greater), but I'm willing to help with small PRs.