Now using C++11 for compatibility; enabled warning
Now using C++11 for compatibility; enabled warning

Divvy v0.5 no longer needs C++14.
C++14 was used for the ease of not implementing std::make_unique myself.
However, I came around and implemented it in the header.

I also enabled warnings so that I can get better messages about my code
and how I'm doing as a programmer. I'm happy to say I only had 3
warnings when I turned it on :) Anyway, I might disable this later if it
becomes to cumbersome to read through when adding new features.

puradox/divvy