subset axis slot in [ method.
set stack as FALSE by default for densitplot
Merge branch 'trunk' into nullGain
wrap overlay calculation in .getOverlay routine. RGLab/flowIncubator#12
fix some doc error
add filterOjbect generic function back
fix all the doc errors and warnings. close #99
add some Rd files
Merge branch 'trunk' into nullGain
Merge branch 'nullGain' of github.com:RGLab/flowWorkspace into nullGain