Expose raw hook event data

[Descolada]

Hello,
Please consider exposing the raw data of hook events, by which I mean in Windows the pointer to KBDLLHOOKSTRUCT/MSLLHOOKSTRUCT and in X11 XKeyPressedEvent. First of all it would allow accessing struct fields not exposed by libuiohook such as KBDLLHOOKSTRUCT->dwExtraInfo, and second it would allow modifying the underlying structure. For example in Windows KBDLLHOOKSTRUCT and MSLLHOOKSTRUCT get propagated down the hook chain, which means we can change how those hooks interpret the data, eg we could remove the LLMHF_INJECTED flag or pass info around using dwExtraInfo.