Use logging (#1718)

* update docs

* plugins: use plugin specific logging

Hooking up pkg/log also changed NewWithPlugin to just take a string
instead of a plugin.Handler as that is more flexible and for instance
the Root "plugin" doesn't implement it fully.

Same logging from the reload plugin:

.:1043
2018/04/22 08:56:37 [INFO] CoreDNS-1.1.1
2018/04/22 08:56:37 [INFO] linux/amd64, go1.10.1,
CoreDNS-1.1.1
linux/amd64, go1.10.1,
2018/04/22 08:56:37 [INFO] plugin/reload: Running configuration MD5 = ec4c9c55cd19759ea1c46b8c45742b06
2018/04/22 08:56:54 [INFO] Reloading
2018/04/22 08:56:54 [INFO] plugin/reload: Running configuration MD5 = 9e2bfdd85bdc9cceb740ba9c80f34c1a
2018/04/22 08:56:54 [INFO] Reloading complete

* update docs

* better doc

1 files changed, 0 insertions, 2 deletions

diff --git a/plugin/reload/reload.go b/plugin/reload/reload.go
index c1803c89d..d04bb037b 100644
--- a/plugin/reload/reload.go
+++ b/plugin/reload/reload.go
@@ -4,8 +4,6 @@ import (
 	"crypto/md5"
 	"time"
 
-	"github.com/coredns/coredns/plugin/pkg/log"
-
 	"github.com/mholt/caddy"
 )