Support for PrintClassHistogramm

[nbartels]

If I use the PrintClassHistogrammBeforeFullGC switch I get some errors.

It would be nice if the parsing errors are gone and it would be awesome if you could support these switches ( PrintClassHistogrammBeforeFullGC and PrintClassHistogramAfterFullGC) so you provide a diff or something of the classes that are removed by fullgc.

[chewiebug]

What jdk version are you using? Could you please attach a sample file?