xcb 1.5.0

Rust safe bindings for XCB
Documentation
This file is an attempt of keeping track of all exceptions introduced in the code generation.
An exception is a difference of code generation based on hard-coded name.

- switch_exceptions (cg/mod.rs)
- mask_exceptions (cg/mod.rs)
- enum exceptions (x::SendEventDest in cg/enum.rs)
- requests that receive event in parameters (cg/request.rs)
- ClientMessageEvent::new: format is inferred from data (cg/event.rs)
- ClientMessageEvent::data: variant inferred from format (handle_client_message_data in cg/struct.rs)
- randr::NotifyEvent::new: sub_code is inferred from u variant (cg/event.rs)
- randr::NotifyEvent::u: variant inferred from sub_code (handle_randr_notify_data in cg/struct.rs)
- xkb unions have a special treatment, the variant is inferred from a type field, hidden to the user (cg/union.rs)
- xinput::Device is faked from DeviceId and is defined in lib.rs (search for "xinput" in cg folder)
- specific documentation for xinput::InputInfoInfo::Button (cg/switch.rs)
- A small part of the XML definitions is hand edited to make the code generation a lot easier.
  and to improve the documentation.
    To check what has been edited, a copy of the upstream definitions is kept under
      - xml/upstream
      - xml/upstream_normalized
    The normalized copy is simply a normalization of indentation to 4 spaces.
    The hand edition is the diff from xml/upstream_normalized to xml.
    Run `diff -ur xml/upstream_normalized xml` to print the diff.