Some Minor improvements. (#77)

* fix bug in docs.

* allow addFields(['foo','bar']) without associations.

* Validation improvement.

* addCondition('foo', ['a','b']); shouldn't touch default.

* style.

docs/relations.rst

@@ -162,9 +162,9 @@ keep making your query bigger and bigger::
 
     $invoice->hasMany('Invoice_Line', new Model_Invoice_Line())
         ->addFields([
-            ['total_vat', ['aggregate'=>'sum']],
-            ['total_net', ['aggregate'=>'sum']],
-            ['total_gross', ['aggregate'=>'sum']],
+            ['total_vat', 'aggregate'=>'sum'],
+            ['total_net', 'aggregate'=>'sum'],
+            ['total_gross', 'aggregate'=>'sum'],
         ]);
 
 

src/Field.php

@@ -68,6 +68,9 @@ class Field
      */
     public function __construct($defaults = [])
     {
+        if (!is_array($defaults)) {
+            throw new Exception(['Field requires array for defaults', 'arg' => $defaults]);
+        }
         foreach ($defaults as $key => $val) {
             $this->$key = $val;
         }

src/Field_SQL_One.php

@@ -40,7 +40,11 @@ public function addField($field, $their_field = null)
     public function addFields($fields = [])
     {
         foreach ($fields as $field => $alias) {
-            $this->addField($field, $alias);
+            if (is_numeric($field)) {
+                $this->addField($alias);
+            } else {
+                $this->addField($field, $alias);
+            }
         }
 
         return $this;

src/Model.php

@@ -627,7 +627,7 @@ public function addCondition($field, $operator = null, $value = null)
             if ($operator === '=' || func_num_args() == 2) {
                 $v = $operator === '=' ? $value : $operator;
 
-                if (!is_object($v)) {
+                if (!is_object($v) && !is_array($v)) {
                     $f->setAttr('default', $v);
                 }
             }