Added directory open/next for windows

[BraedonWooding]

I haven't tested it yet on a windows computer, I'll do that later tonight. Was much easier to implement in the end (they even gave a nice C example which made it extremely easy to build). In saying that I will do some more intensive testing later today.

It is slightly awkward to do windows file 'searching' as to open it you need to search the first file then you search for each 'next file' which means that it is finding the next file before returning the current file, which means I have to malloc the name into the buffer, luckily however I don't need the buffer for anything else so that kind of worked out :).

This fixes #709 and is required for #1068

Note: removed the 'if check' under docgen.zig as that is no longer needed :D.

All stuff changed

• Removed if condition in docgen to re-enable feature on windows
• As to support windows Dir struct the 'DirData' field is dependent on OS
• Implemented windows.PathIsDirectoryEmpty
• Implemented windows.RemovedDirectory
• Implemented windows.FindFirstFile
• Implemented windows.FindNextFile
• Implemented windows.FindClose
• Implemented windows.WIN32_FIND_DATA struct
• Implemented windows_util.FileSearchData containing all the data required for future searches (as well as the current file pointer and if you are at the 'end').
• Implemented windows_util.windowsPathIsDirectoryEmpty
• Implemented windows_util.windowsRemoveDirectory
• Implemented windows_util.windowsFindFirstFile
• Implemented windows_util.windowsFindNextFile
• Implemented windows_util.windowsFindClose

[BraedonWooding]

I'll squash once the checks pass :) (I'll also remove all the extra file junk)

[BraedonWooding]

Re-opening in another PR since when fixing it on windows it stuffed up my git rip :(.