nico package not found
I've just installed nim on my Win10 x64 system and successfully made a helloworld.nim program.
I now tried installing nico with `nimble install nico` and got the following output:

```bash
$ nimble install nico --verbose
    Reading official package list
    Prompt: nico not found in any local packages.json, check internet for updated packages? [y/N]
    Answer: y
Downloading Official package list
     Trying https://github.com/nim-lang/packages/raw/master/packages.json
    Success Package list downloaded.
    Reading official package list
     Error: Package not found.
```