modified validate class variable to conform to naming convention of private/protected variables beginning with an underscore
added documentation
added some code documentation, modified setFlash function to accept an array of messages rather than simply a string
added errors class variable to keep track of errors and error messages when saving, validating, etc. If there is a failure, you can then simply access the errors array to get the information rather than edit Session variables (flash messages) inside of the model. removed session component from model. renamed a few variables so the naming convention is: private/protected are prefixed by underscores.