fuel/core — pull request #1786 by aaharu (2014-10-18 14:52:03+00:00)
Title: Update XML boolean format.

http://www.w3.org/TR/xmlschema-2/#boolean
> An instance of a datatype that is defined as ·boolean· can have the following legal literals {true, false, 1, 0}.

```php
array('true' => true, 'false' => false)
```

**current format**
```xml
1
```
`false` is formatted to empty string.

**this format**
```xml
truefalse
```
or
```xml
10
```

Signed-off-by: Haruaki Otake