Increase viewangles roll limit to 180

[fabiolimamp]

Quake historically puts a limit of 50 degrees for the player's v_angle Z component.

This limit seems arbitrary however, since the Z roll angle "sticks" and must be managed by the mod either way, and nothing breaks with it increased.

[sezero]

@ericwa, @andrei-drexler: comments, objections?

[andrei-drexler]

This looks like a sensible change, but maybe it should be controlled by a cvar (cl_maxroll, defaulting to 180)? That would make it consistent with the pitch limits (cl_minpitch/cl_maxpitch) and it would allow purists to go back to the original behavior by setting it to 50.

[fabiolimamp]

Per @andrei-drexler suggestion, updated the PR with a new cl_maxroll cvar defaulted to 180.