add activity priorities to core so that other apps can reuse it

Issue/6101 Autoload preview providers

Skip lostcontroller sending email test on windows

Add notes that SQLite is CE only

Add functions to modify cookies to response class

Issue/6101 Make all interfaces/classes autoloadable

Limit blacklist to php files

During performance optimization I have discovered that the installer scans all files for the blacklisted words. This greatly impacts speed on lower end devices such as the raspberry pie. This commit limits it to PHP files which seems to achieve the desired effect. 

I have used the --include option to achieve this, see http://stackoverflow.com/questions/1987926/how-do-i-grep-recursively

This contribution is MIT licensed

So the class files only have class code and don't execute code

Add Jail and PermissionsMask storage wrappers

Jenkins 12447

Introduce buildPath() in Storage\Local to reduce the difference to MappedLocal

Currently there is no AppFramework way to modify cookies, which makes it unusable for quite some use-cases or results in untestable code.

This PR adds some basic functionalities to add and invalidate cookies.

Usage:
```php
$response = new TemplateResponse(...);
$response->addCookie('foo', 'bar');
$response->invalidateCookie('foo');
$response->addCookie('bar', 'foo', new \DateTime('2015-01-01 00:00'));
```

Existing cookies can be accessed with the AppFramework using `$this->request->getCookie($name)`.

Issue/12444 namespace exceptions

delete old previews

Cache results of available languages

Move constants from GET_TYPE to OC\Files so they can be autoloaded

This function is about 8 times calles for every single page call, when caching this variable I was able to gain a small performance improvement from 20,512 µs to 630 µs profiled with xhprof

Surely, this is no gigantic gain but if we would do that for every function out there...

added comment that App Store is disabled for EE