#150 start caching plex media as well. refactored the availability checker. NEEDS TESTING. also, we need to make the Requests hit the plex api directly rather than hitting the cache as it does now.

PlexRequests.Api.Models/Plex/PlexLibraries.cs

@@ -0,0 +1,22 @@
+using System.Collections.Generic;
+using System.Xml.Serialization;
+
+namespace PlexRequests.Api.Models.Plex
+{
+    [XmlRoot(ElementName = "MediaContainer")]
+    public class PlexLibraries
+    {
+        [XmlElement(ElementName = "Directory")]
+        public List<Directory> Directories { get; set; }
+    }
+
+    [XmlRoot(ElementName = "Location")]
+    public partial class Location
+    {
+        [XmlElement(ElementName = "id")]
+        public int id { get; set; }
+        [XmlElement(ElementName = "path")]
+        public string path { get; set; }
+    }
+
+}