Make preprocessor directive parsing less buggy

[Cheatoid]

Modified to enforce directives be at the beginning of the line, while still allowing leading whitespace

So for example, if you have:

--@client
print("--@server") --@name not allowed here anymore
         --@model however/this/is/fine.mdl

This PR solves it simply by prepending a newline and allowing leading whitespace, therefore the "--@server" and --@name would no longer match in the above case.

[thegrb93]

Idk, what if someone likes to do stuff like require("mylib.txt") --@include mylib.txt? Their chips will be broken.

[Cheatoid]

Idk, what if someone likes to do stuff like require("mylib.txt") --@include mylib.txt? Their chips will be broken.

Yes, PR is a breaking change in that regard.
Maybe just introduce a new directive to fix that once and for all.

--@import mylib.txt

and it would expand into what you've posted, then we can move on. Want me add that?
They can simply regex-replace it to migrate/fix their scripts if they really have such.
I think you shouldn't have directives embedded together with the actual code on the same line in the first place.

[thegrb93]

I don't think there's a good general way to implement that. Special cases like this exist libs.mylib = require("mylib.txt") --@include mylib.txt. I guess you could do libs.mylib = --@require mylib.txt if the changes in this PR are reverted.

[thegrb93]

I do think the directive matching could be improved if the iterator is changed to SF.GetLines and better matching is done per line though. I would want to test the performance difference on a big file to make sure it isn't too costly though.