Added support for manually passing validations

Added support for manually passing validations to the $this->validate()
method.  You can now create a multidimensional array, which will
manually set validations, as well as perform the automatic validations.
Array must look like this:

$manual_validations=array(
'fieldname'=>array(
'name'=>'Field Name',
'rules' => 'rule1|rule2|rule3'
),
etc.
);

You can pass as manu manual validations as you like as long as you
follow this convention.  The 'name' index is the proper name that will
be displayed in the error message.  The rules is a pipe-delimited set of
CodeIgniter defined rules. Note: pipe-delimited rules cannot have a
space between the rules.
Further information on validations

Added some proper names to certain abbreviated fields (month, year,
hours, minutes) for automatic validations.

Also added further explanation of manual validations .