Some minor code tidying.
Added 'base' attribute to flow; some tidying
Added test & fix for new xml:base handling
Minor tidying while compiling documentation
Fixed handling of division yielding infinity.
Further tidy of code before refactoring
Fixed one of the STOMP examples
Tidied up method naming in Assert helper class
Started refactoring of validation/notifications
Continued refactoring of existing validation API
Refined new API - simpler but easier to extend
Replaced CardinalityValidationError
Replaced ItemFlowValidationError
Renamed use of ValidationContext for consistency
Refactored old ValidationItem hierarchy
Started to replace RuntimeValidationResult et al
Started to add notification tracking to GUI
Refactored candidate event log; init now recorded
Added notifications count to candidate log
Integrated notifications into rendering