'triton insts' default output changes

Change default short and --long output of 'triton insts' somewhat
per feedback from Angela.

I also dropped validFields and turned on dottedLookup so you can do
stuff like:
    triton insts -o shortid,name,tags.foo,metadata.root_authorized_keys

lib/do_instances.js

@@ -20,38 +20,18 @@ var validFilters = [
     'credentials'
 ];
 
-// valid output fields to be printed
-var validFields = [
-    'id',
-    'name',
-    'type',
-    'state',
-    'dataset',
-    'memory',
-    'disk',
-    'ips',
-    'metadata',
-    'created',
-    'updated',
-    'package',
-    'image',
-    'img',
-    'ago',
-    'shortid'
-];
-
 function do_instances(subcmd, opts, args, callback) {
     if (opts.help) {
         this.do_help('help', {}, [subcmd], callback);
         return;
     }
 
-    var columns = 'shortid,name,state,type,img,memory,disk,ago'.split(',');
+    var columns = 'shortid,name,img,state,primaryIp,ago'.split(',');
     if (opts.o) {
         /* JSSTYLED */
         columns = opts.o.trim().split(/\s*,\s*/g);
     } else if (opts.long) {
-        columns[0] = 'id';
+        columns = 'id,name,img,package,state,primaryIp,created'.split(',');
     }
     /* JSSTYLED */
     var sort = opts.s.trim().split(/\s*,\s*/g);
@@ -116,7 +96,7 @@ function do_instances(subcmd, opts, args, callback) {
                 skipHeader: opts.H,
                 columns: columns,
                 sort: sort,
-                validFields: validFields
+                dottedLookup: true
             });
         }
         callback();
@@ -151,8 +131,8 @@ do_instances.options = [
     {
         names: ['s'],
         type: 'string',
-        default: 'name',
+        default: 'created',
-        help: 'Sort on the given fields. Default is "name".',
+        help: 'Sort on the given fields. Default is "created".',
         helpArg: 'field1,...'
     },
     {