Added checking if session table exists before creating it in the session task

Signed-off-by: Derek Myers <arcticpro@gmail.com>
Fixed Event_Instance::unregister() bug
Merge pull request #1355 from indigofeather/1.6/develop

Fixed Event_Instance::unregister() bug
Merge pull request #1353 from dmyers/bugfix/session-task

Improved session task for creating table
Add _validation_date and tests
fixed bug in the error handler that made trigger_error() calls not catchable
fixed broken pagination tests. Closes #1352
Change validation name. (date -> valid_date)
Fix tests
Merge pull request #1357 from hackoh/1.6/add_validation_date

Propose _validation_date
Fix issue #1359

Remove of unused $db and remove the option of passing a Database_Connection instance for $connection
Merge pull request #1362 from daidais/patch-1

Fix issue #1359
enable a per-controller auth strategy for Controller_Rest/Hybrid
Added $_mass_whitelist/blacklist to Model_Crud

For example I have Model_Customer to work with and it's ok.

Now I need Model_Customer_Api which would extend the Model_CUstomer, but I want only fields like:

```php
	protected static $_mass_whitelist = array(
		'first_name',
		'last_name',
	);
```
to be changed from Api model, but not others. so I pass only those fields.

Also made the mass_blacklist, so we can blacklist for example 'username' field, where api won't be able to change the username.


Thanks,
huglester
typo
moved security settings back to app; added filter on duplicate security filters
Merge pull request #1365 from huglester/patch-2

Added $_mass_whitelist/blacklist to Model_Crud
fixed fieldset::populate with zero field values. Closes #1367
Merge branch '1.6/develop' of https://github.com/fuel/core into 1.6/develop
Fix Fuel::STAGE const name and value

Signed-off-by: Kenji Suzuki <kenji.uui@gmail.com>