Use X11 protocol directly via libxcb, instead of xhost command

[intgr]

XCB seems to solve all the issues that the initial attempt with libX11 had (#89 (comment))

Closes #89

[intgr]

Maybe consider the xcb-dl crate instead, which lazily loads libxcb library only if needed?

https://docs.rs/xcb-dl/latest/xcb_dl/struct.Xcb.html#method.xcb_change_hosts

[intgr]

Maybe consider the xcb-dl crate instead, which lazily loads libxcb library only if needed?

Nah, it seems more complicated. Real desktop systems almost certainly still have X11 and libxcb installed.

[intgr]

Possibly one day, rust-xcb upstream will implement this as well:

• Support loading libxcb.so and friends through dlopen rust-x-bindings/rust-xcb#88