src/webapp/base-controller.php: Explicitly define 'context' as a class attribute; add explicity type declaration for parameter of method 'dispatch'; remove unnecessary definition for $content variable; add XXX comment re 'user' attribute.
src/test/webapp.php: Some minor tidying...
src/test/webapp.php: Instead of raising a generic TestFailure when 'submitForm' method finds resulting error messages, raise a ValidationErrors exception (which sub-classes TestFailure).
src/webapp/forms.php: When validating DollarAmountField, do not check for 'maxAmount' if no 'maxAmount' was ever specified; plus add relevant test cases for 'maxAmount' functionality.