Reimplemented the elrpc client

[RSDuck]

Originally I wanted to improve the elrpc and the elparser library but then I thought screw it. The procol is so simple, in the time, I would need to find the cause for the lag spikes, I could also rewrite the library. And that's what I've done. It acts as a complete replacement and hasn't got these weired lag spikes and is less code.

I only tested it with nimsuggest from devel on Windows, so there might be some problems, but I think there aren't. In the files I've created, I changed the copyright notice to Xored Software Inc., RSDuck. I hope this is ok.

In the signature provider I removed the - 1 before the column. Otherwise the signature provider wouldn't work on devel nimsuggest(and future releases). I don't know if it still works with stable Nim, otherwise I would wait until Nim 0.17 with merging this pull request or making a new release of the extension. And as the last change I added support for code blocks in documentary comments.

[kosz78]

Great, thank you for your contribution
According backward compatibility you can use isNimSuggestVersion for nimsuggest version check

[RSDuck]

I did some checks, all changes work flawlessly with latest stable Nim, so that's not a problem