Added basic time editing.

The button presses don't work yet as YouTube steals the events.

public/_locales/en/messages.json

@@ -479,5 +479,9 @@
     },
     "keyAlreadyUsed": {
         "message": "is bound to another action. Please select another key."
+    },
+    "to": {
+        "message": "to",
+        "description": "Used between sponsor times. Example: 1:20 to 1:30"
     }
 }

public/content.css

@@ -330,4 +330,24 @@
 	font-size: 13px;
 	
 	cursor: pointer;
+}
+
+.sponsorTimeEdit > input::-webkit-outer-spin-button,
+input::-webkit-inner-spin-button {
+  -webkit-appearance: none;
+  margin: 0;
+}
+
+.sponsorTimeEdit {
+	font-size: 14px;
+
+	-moz-appearance: textfield;
+}
+
+.sponsorTimeEditMinutes {
+	width: 30px;
+}
+
+.sponsorTimeEditSeconds {
+	width: 60px;
 }