Can't set loglevel of subsystems properly

I have a package that has a lot of subpackages. The loggers get initialized like this for each package;

```go
var log = log2.Logger("hwdata:cli")
var log = log2.Logger("hwdata:system")
var log = log2.Logger("hwdata:cpu")
```

When I include this project into another project, I want to set all the loglevels of this subsystem to info;
```bash
GOLOG_LOG_LEVEL="debug,hwdata=info" go run .
```

This doesn't work. It still shows `hwdata:cpu` with level debug.
Then I tried the "regex" setup that was described in the readme.md;
```bash
GOLOG_LOG_LEVEL="debug,hwdata:.*=info" go run .
```

This also doesn't work

I now have to write it like this;
```bash
GOLOG_LOG_LEVEL="debug,hwdata:cpu=info,hwdata:system=info,hwdata:cli=info" go run .
```

which is kind of ineffective, especially since I have about 20 of those subsystems. Shouldn't this just work on a subsystem level basis? Or is the ":" that is mentioned in the readme just arbitrary and doesn't it work with subsystems like that at all?