added filter name param to DumpFrames
nsViewerApp.cpp
added -o <outputDirPath> for specifying where output files should go
added -filter <filterName> for specifying that <filterName> should be used in an automated fashion for
dumping frames for every URL visited.
nsWebCrawler.cpp,h
added support methods to handle output dirs, output file name building from URL, and filter names
added DumpFrames to ::OnStopBinding when the right state is set (from -filter option)
added dependancies on: nsIPresShell.h, nsIPresContext.h, and nsIFrame.h
