`vagrant up` can be used the same as `vagrant resume` [closes GH-134]

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## 0.5.2 (unreleased)
 
+  - `vagrant up` can be used as a way to resume the VM as well (same as
+    `vagrant resume`). [GH-134]
   - Sudo uses "-E" flag to preserve environment for chef provisioners.
     This fixes issues with CentOS. [GH-133]
   - Added "IdentitiesOnly yes" to options when `vagrant ssh` is run to

lib/vagrant/vm.rb

@@ -103,6 +103,7 @@ module Vagrant
 
     def start
       return if @vm.running?
+      return resume if @vm.saved?
 
       env.actions.run(:start)
     end

test/vagrant/vm_test.rb

@@ -203,6 +203,7 @@ class VMTest < Test::Unit::TestCase
     context "starting" do
       setup do
         @mock_vm.stubs(:running?).returns(false)
+        @mock_vm.stubs(:saved?).returns(false)
       end
 
       should "not do anything if the VM is already running" do
@@ -211,6 +212,13 @@ class VMTest < Test::Unit::TestCase
         @vm.start
       end
 
+      should "execute the resume action if saved" do
+        @mock_vm.expects(:saved?).returns(true)
+        @vm.expects(:resume).once
+        @vm.env.actions.expects(:run).with(:start).never
+        @vm.start
+      end
+
       should "execute the start action" do
         @vm.env.actions.expects(:run).with(:start).once
         @vm.start