Support directives in ENS configurations, such that subdomains can be registered to addresses of deployed tokens.
The following directives are supported:
```
"register": {
"rootDomain": "embark.eth",
"subdomains": {
"status": "0x4a17f35f0a9927fb4141aa91cbbc72c1b31598de",
"mytoken": "$MyToken",
"MyToken2": "$MyToken2"
}
}
```
Add unit test for these directives.
emizzle