Add wlan station and interface metrics collection. (#14)

* Fix newlines.
* Added wlan metrics.
* Fix WlanSTA collector - return on errors.

config/test/config.test.yml

@@ -1,19 +1,21 @@
----
-
-devices:
-  - name: test1
-    address: 192.168.1.1
-    user: foo
-    password: bar
-  - name: test2
-    address: 192.168.2.1
-    user: test
-    password: 123
-
-features:
-  bgp: true
-  dhcp: true
-  dhcpv6: true
-  routes: true
-  pools: true
-  optics: true
+---
+
+devices:
+  - name: test1
+    address: 192.168.1.1
+    user: foo
+    password: bar
+  - name: test2
+    address: 192.168.2.1
+    user: test
+    password: 123
+
+features:
+  bgp: true
+  dhcp: true
+  dhcpv6: true
+  routes: true
+  pools: true
+  optics: true
+  wlansta: true
+  wlanif: true