Change the order of arguments for snapshot.

This is related to #10. Although I was unable to reproduce this
error on my system, I assume that providing a required argument
after a non-required argument was breaking Thor in some way.

Either way, this is a saner way to do it.

README.md

@@ -103,7 +103,7 @@ match.
 
 ### Snapshot a droplet
 
-    $ tugboat snapshot admin test-admin-snaphot
+    $ tugboat snapshot test-admin-snaphot admin
     Queuing snapshot 'test-admin-snapshot' for 13231512 (pearkes-admin-001)...done
 
 ## Help

lib/tugboat/cli.rb

@@ -159,7 +159,7 @@ def info(name=nil)
       })
     end
 
-    desc "snapshot FUZZY_NAME [OPTIONS]", "Queue a snapshot of the droplet."
+    desc "snapshot SNAPSHOT_NAME FUZZY_NAME [OPTIONS]", "Queue a snapshot of the droplet."
     method_option "id",
                   :type => :string,
                   :aliases => "-i",
@@ -168,11 +168,7 @@ def info(name=nil)
                   :type => :string,
                   :aliases => "-n",
                   :desc => "The exact name of the droplet"
-    method_option "snapshot",
-                  :type => :string,
-                  :aliases => "-s",
-                  :desc => "The name of the snapshot"
-    def snapshot(name=nil, snapshot_name)
+    def snapshot(snapshot_name, name=nil)
       Middleware.sequence_snapshot_droplet.call({
         "user_droplet_id" => options[:id],
         "user_droplet_name" => options[:name],

lib/tugboat/middleware/find_droplet.rb

@@ -11,7 +11,7 @@ def call(env)
         # First, if nothing is provided to us, we should quit and
         # let the user know.
         if !user_fuzzy_name && !user_droplet_name && !user_droplet_id
-          say "Tugboat attempted to find a droplet with no arguments.", :red
+          say "Tugboat attempted to find a droplet with no arguments. Try `tugboat help`", :red
           return
         end