Security Path + new BMP loader + Themes's inheritance

This pull request contains three modifications.

- **A security patch**
I found another critical exploit in your CP, currently possible to include local files by hacking your "Theme switcher" mod.
It allow, without restriction to execute all files from your webhost, and possibly abuse to upload a backdoor as image and include it again to execute it.
The exploit should not work in all servers, it can depend of the OS and also of the PHP version to hack the filesystem (*null byte poisoning*, *path truncation*, ...), but in all case should be fix as soon as possible.

- **A faster and cleaner BMP loader.**
The old one was written by MagicalTux very long long time ago and some improvements were possibles as to clean up the code. This new file is based on my roBrowser's remote client, faster, cleaner and free to use. *(To be honest, I didn't check on a live server this script after some little modifications - no available emblem data - but should just works fine)*

- **Theme inheritance**
This big commit was made to avoid duplicating each files from the templates each time you need to make a new one. It introduce some problems as the security patch I released some weeks ago that break custom themes.
So how it works : in template folder, create a new folder called "test", add it a manifest.php file that return an array :
```php
<?php
 return array(
 	'inherit'     => 'emphaino',
 );
 ?>
```
That's all, you don't need to add any other files to use this new theme.
It will inherit all view, css, images from the emphaino theme which will inherit from default theme.
So if in future you modify a file in the default template, the change will be propagate to all themes.

And for customers, just need to release a manifest.php file, header.php/footer.php and images/css to make the theme works.

**Note:** it also work for addons themes, so if you change the theme, you do not need to duplicate addons theme's folder.

*Have suggestions or improvements ?*