Simplifying bitflags

[SonnyX]

Another potential way to improve code, albeit at the expense of adding another dependency
master...Alovchin91:feature/bitflags

[pravic]

But it's safer. I have to do this eventually.

[SonnyX]

Here is another repo implementing some more bitflags, along with mutability changes and other improvements:
master...kwdkk:master

[pravic]

Yeah. The bitflags is a total win but other changes seem controversial and arguable.