New: Added Admin page (fixes #30)

Fixes #30

Following are the changes made:

* Supports save and reload of config.
* Picks up the config with a higher priority as mentioned in the README.
* Runs with ```grunt admin```
* Uses react and coffeescript

Any suggestions on how to go about on the below points?

* Support of https ( Need certificates. Related to #58? )
* Restart of other servers on save. (Should ```example.coffee``` be made a module?)
* Graph ( depends on #10 )
On many systems this will probably fail because the `/etc/dnschain/dnschain.conf` file could be owned by root.

If the write failed due to insufficient permissions, can you simply display the following error?

> Could not write to `[file path]`, please make sure that this file is writable by the user that DNSChain is running as.