Add methods to access specific properties from a Fieldset

* GetValue("alias") - gets the value as a string
* GetValue<T>("alias") - attempts to convert to the specified types using some of Umbraco's built in TypeConverter logic.  If conversion fails, returns default(T).  Note this doesn't utilize PropertyValueConverters (yet?)
* GetProperty("alias") - gets a reference to the entire property object.  Leaving this private for now, but there may be a reason to publicize someday if we add more properties to the Property object.

app/Umbraco/Umbraco.Archetype/Models/Fieldset.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using Umbraco.Core;
 
 namespace Archetype.Umbraco.Models
 {
@@ -16,5 +17,30 @@ namespace Archetype.Umbraco.Models
             Properties = new List<Property>();
         }
 
+        public string GetValue(string propertyAlias)
+        {
+            return GetValue<string>(propertyAlias);
+        }
+
+        public T GetValue<T>(string propertyAlias)
+        {
+            var property = GetProperty(propertyAlias);
+
+            if (property == null || string.IsNullOrEmpty(property.Value))
+                return default(T);
+
+            var convertAttempt = property.Value.TryConvertTo<T>();
+
+            if (convertAttempt.Success)
+                return convertAttempt.Result;
+
+            return default(T);
+        }
+
+        private Property GetProperty(string propertyAlias)
+        {
+            return Properties.FirstOrDefault(p => p.Alias.InvariantEquals(propertyAlias));
+        }
+
     }
 }