ZF-1877: Add error message codes and tokens to validation classes' documentation

Description

The documentation for Zend_Filter_Input states:

bq. You should refer to documentation for each validator class to know if it has multiple error messages, the keys of these messages, and the tokens you can use in the message templates.

Indeed, the documentation of the validation classes should include such information.

Comments

This issue should have been fixed for the 1.5 release.

Must Have for Next Mini Release.

Oops, Should Have

Integrated with r14255