Some minor CS improvements to FormHelper

Replaced use of deprecated method getVar by get.
Improved DocBocks, mostly data types
Removed deprecated DocBock tag because it's an invalid use of such. This makes the method look like it was deprecated but in reality it's only one of the possible values of one of its parameters.
Some love for a deprecated class

Whitespace and wording.

Optionally we could include a version number until when this class will work. I assumed this will be 3.0...
http://www.phpdoc.org/docs/latest/for-users/phpdoc/tags/deprecated.html
I treid that but after I let apigen generate the doc and I saw it did nothing special about it ;-/
Merge pull request #1407 from ravage84/patch-2

Some love for a deprecated class
Merge pull request #1406 from ravage84/formhelper

Some minor CS improvements to FormHelper