ZF-3572: Alter Zend_Form components to lazy-load


Currently, the plugins in Zend_Form -- elements, decorators, validators, and filters -- are always instantiated immediately on attachment when the string form of the plugin is used. This causes issues with concurrency and workflow when building forms.

The solution is to load them only on-demand -- either at get() time or gets() time -- i.e., lazy loading.

This will particularly help use cases when decorators are attached late.


Fixed in r9919