Added Validation Block field when creating a question. This allows validation of the answer entered by the user. This is especially useful in a registration assessment -- it allows the email entered to be checked if it already exists and prevent the assessment from continuing.
The value of this field must be multiples of a TCL boolean expression and an error message separated by spaces.
Added an option for select box widgets to prepend an empty option, this is useful for instances where the field is required but you don't want a default to be selected but also don't want the options to be ordered by random