Some semantic changes

[opfromthestart]

Conglomerated server and client, along with their flags, into an enum called ServerClient, that handles either, and is actually exclusive.

• Make better name for ServerClient

Replaced vsync sentinel values with VSyncMode enum.
Path.is_dir and Path.is_file return false if the path is broken, so they can be used instead, and actually do what they are named.
match changed to matches! for ease of reading.