Zend_View: accessing view variables with value null throws error when strictVars is active

[pluspolleipzig]

When assigning null to a view variable it's not possible to access it from the view when strictVars is active.

This is because of the following isset() check which returns false for null values:
https://github.com/Shardj/zf1-future/blob/master/library/Zend/View/Abstract.php#L277

I think the fix would be using array_key_exists() instead.

Line 300 might also be affected by this:
https://github.com/Shardj/zf1-future/blob/master/library/Zend/View/Abstract.php#L300