Add cancel button for edit log.

Disable edit button for past month
Format gas correctly

Web/Attributes/DenyPreviousMonthDateAttribute.cs

@@ -1,5 +1,6 @@
 using System;
 using System.ComponentModel.DataAnnotations;
+using MileageTraker.Web.Models;
 
 namespace MileageTraker.Web.Attributes
 {
@@ -13,8 +14,9 @@ namespace MileageTraker.Web.Attributes
 
 		private static DateTime GetCutoff()
 		{
-			var today = DateTime.Today;
-			return today.AddMonths(-1).AddDays(-today.Day + 1); // last two months
+			return DomainRules.GetLogEntryCutoff();
+			//var today = DateTime.Today;
+			//return today.AddMonths(-1).AddDays(-today.Day + 1); // last two months
 			//if (today.Day > 10)
 			//	return today.AddDays(-today.Day); // beginning of this month
 			//return today.AddMonths(-1).AddDays(-today.Day); // beginning of previous month