added Creator class for filters
added description field to filter record
basic filter tree structure
added filter box and basic record filter UI (not functional yet; only supporting on-the-fly filters for now)
repalced std::auto_ptr with boost::shared_ptr in filter nodes
replaced binary filter node with a n-ary node
added parser and custom filter edit widget (parser not functional yet; always returns a false boolean node)
fixed BooleanNode constructor
apply filter to table after filter text change
automatically build column map on filter change
added error reporting in the filter edit widget (change the text colour for now)
some general filter parser cleanup
Silenced some warnings
Remove an unused method
Use separate inputs for swimming and flying
Avoid swimming into the air from underwater
Non-colliding objects are considered flying
Use a proper node hierarchy; disconnect the root when entering interior
Fix composite map for cells without land data
Fix a material issue, layers per pass wasn't entirely correct