Automatic escaping of default values

It is now possible to use `\` in non-escaped default values for a column,
and it will be automatically escaped for platforms that need it.

Previously this lead to a confusion when diffing actual and expected
schema leading to perpetual out of sync schema.

Before:

```php
/**
 * @ORM\Column(options={"default" = "Foo\\Bar"}))
 */
private $name;

```

After:

```php
/**
 * @ORM\Column(options={"default" = "Foo\Bar"}))
 */
private $name;

```

And the result in database will be a default value exactly as written in
the annotation, that is `Foo\Bar`.

lib/Doctrine/DBAL/Platforms/AbstractPlatform.php

@@ -2306,7 +2306,7 @@ abstract class AbstractPlatform
             return " DEFAULT '" . $this->convertBooleans($default) . "'";
         }
 
-        return " DEFAULT '" . $default . "'";
+        return " DEFAULT " . $this->quoteStringLiteral($default);
     }
 
     /**

tests/Doctrine/Tests/DBAL/Platforms/AbstractMySQLPlatformTestCase.php

@@ -907,4 +907,15 @@ abstract class AbstractMySQLPlatformTestCase extends AbstractPlatformTestCase
         self::assertContains('bar', $sql);
         self::assertNotContains('DATABASE()', $sql);
     }
+
+    public function testGetDefaultValueDeclarationSQLEscaped()
+    {
+        // string must be escaped
+        $field = array(
+            'type' => 'string',
+            'default' => 'Foo\\Bar'
+        );
+
+        self::assertEquals(" DEFAULT 'Foo\\\\Bar'", $this->_platform->getDefaultValueDeclarationSQL($field));
+    }
 }

tests/Doctrine/Tests/DBAL/Platforms/AbstractPostgreSqlPlatformTestCase.php

@@ -976,4 +976,15 @@ abstract class AbstractPostgreSqlPlatformTestCase extends AbstractPlatformTestCa
             true
         );
     }
+
+    public function testGetDefaultValueDeclarationSQLEscaped()
+    {
+        // string must be escaped
+        $field = array(
+            'type' => 'string',
+            'default' => 'Foo\\Bar'
+        );
+
+        self::assertEquals(" DEFAULT 'Foo\\\\Bar'", $this->_platform->getDefaultValueDeclarationSQL($field));
+    }
 }

tests/Doctrine/Tests/DBAL/Platforms/OraclePlatformTest.php

@@ -874,4 +874,15 @@ EOD;
     {
         self::assertContains("'Foo''Bar\\\\'", $this->_platform->getListTableColumnsSQL('foo_table', "Foo'Bar\\"), '', true);
     }
+
+    public function testGetDefaultValueDeclarationSQLEscaped()
+    {
+        // string must be escaped
+        $field = array(
+            'type' => 'string',
+            'default' => 'Foo\\Bar'
+        );
+
+        self::assertEquals(" DEFAULT 'Foo\\\\Bar'", $this->_platform->getDefaultValueDeclarationSQL($field));
+    }
 }