Reimplement event handler

[ttytm]

This is probably the most complicated change I'm going to suggest here. It is a breaking change. But the improvements hopefully outweigh this.

The PR has following changes that are related to each other

• Moves towards better utilizing the WebUI C library to bind functions.
• Removes the need of additionally storing the callbacks in an global variable Usually, global variables in V are only allowed when a user passes the -enable-global flag. Currently, this flag isn't necessary due to (mis)usage of the [translated] attribute. The attribute also deactivates several other functionalities and checks. Usually it's only for automatically generated C code. Resolving this reduces the potential for future breaking changes.
• Uses a void bind callback that resembles it's parent C function. Removes the need to add e.g. return 0 to every bound function even when it doesn't return anything. If functions should return values to JS the Events return method can be used, e.g.: e.@return(my_number).
• Event string-, int- and bool-data can be accessed with the new equivalent Event methods.
• Updates the bind function to return the bound Functions id instead of the window id on which the function was called on.
• Uses usize for size_t types
• Updates, cleanups and fixes spelling in examples
• Implements the new event size field
• Adds doc comments for public function and organizes the library
• Implements the new function to set the default root folder

Result: https://github.com/ttytm/v-webui/blob/refactor/reimpl-event-handling/src/lib.v.

It might be easiest to look at the commits separately to follow the changes. It's a lot so sorry about the headache. I hope you find your way trough and please let me know if something is unclear or should be changed.

[malisipi]

event.@return is used in history. It was changed for native event handling system. However i can understood that is important for removing [translated]. Using old approach is better way to make the library more stable. https://github.com/webui-dev/v-webui/blob/bdb4e10e6d5a45396b6311cb8e675e928772c3e9/examples/call_v_from_js.v#L37-L39

Also this PR is resolving some unsafe behavior of library. (You can blame me for this behaviors of library :D) https://github.com/webui-dev/v-webui/blob/c7f8d03a6b009a4d0c9fc122da43ae23947ee2dc/src/lib.v#L73-L77

After all, this PR will make everything more stable and it's required for avoid breaking changes in future.

[ttytm]

Thank you for you review @malisipi!

It was good to add it to make the experience with with this approach! I see myself having implemented it in some form, but then realizing after some weeks that it's good the way the C library does and looking for a good moment to reverted it 🙈. I think it won't hurt us to stay true to the parent libraries approach here, on the contrary. Now, with the upcoming version and other other API related / breaking changes that are made to all wrappers it is probably a good moment for such a move.

[ttytm]

Also this PR is resolving some unsafe behavior of library.

I actually didn't changed this script function in this PR

pub fn (window Window) script(javascript string, timeout u64, size_buffer int) string { 
    response := &char(' '.repeat(size_buffer).str) 
    C.webui_script(window, &char(javascript.str), timeout, response, size_buffer) 
    return unsafe { response.vstring() } 
} 

But I think we can upgrade it to make it safer and include all features. I submitted something here: #49

[malisipi]

Oh, i guess i misread the diff file. (Nevermind)

I haven't enough knowlenge about C/V interopability to implement this better. So I wrote this code even I know this is not safe. However refactoring this code is really good. And I thank you for it.

[ttytm]

Thank you @malisipi. Your code is good. Everything else now builds on that!