Add domain and subdomain support for MinioAPI

This change brings in domain and subdomain support

   - ./minio --domain "yourminiodomain.com"

This change brings in a much needed feature by keeping
bucketnames as part of your 'DNS' name.

All your existing applications can be migrated off from s3 to
Minio without little to no modifications.

NOTE: Setting up DNS for your `buckets` is out of scope of this feature

pkg/server/server.go

@@ -31,6 +31,7 @@ import (
 )
 
 type ServerConfig struct {
+	Domain   string
 	Address  string
 	Tls      bool
 	CertFile string
@@ -78,7 +79,7 @@ func getHttpChannels(configs []ServerConfig) (ctrlChans []chan<- string, statusC
 
 				ctrlChans, statusChans, storage = getStorageChannels(k.StorageType)
 				// start minio api in a web server, pass storage driver into it
-				ctrlChan, statusChan, _ = httpserver.Start(minioapi.HttpHandler(storage), httpConfig)
+				ctrlChan, statusChan, _ = httpserver.Start(minioapi.HttpHandler(config.Domain, storage), httpConfig)
 
 				ctrlChans = append(ctrlChans, ctrlChan)
 				statusChans = append(statusChans, statusChan)