Update AclHelper.php

Correction of variable name used throughout getAllowedActionsByUserId(), swapped from $roleId to $userId
Fixed a bug in updateAll as modelAlias.id could not be an array - refs #451
BlocksComponent: Accept ',' for multiple values in conditions

Eg: `[node:recent conditions="Node.type:article,news;"]`

Closes #457
If admin_theme enabled, add theme's helper path

Closes #463
Replace forced escape values with default values

The prev() and next() escape values were forced to false, first() and last() were forced to true

Now these values are only set if user does not pass escape value from view.

Closes #465
Avoid notice when plugin description is missing
Merge remote-tracking branch 'upstream/master' into 1.5.ready