experimental
finished slicing angle adjustment
improved slicing, steeper mapping curve
improved tracking of unpreprocessed data
Merge branch 'master' into yong_experimental

Conflicts:
	fluorender/FluoRender/FLIVR/ImgShader.cpp
fixed some problems in cell tracking
interactive setting influences sliders as well
chenged the color of the selection when a label volume it present
reverted back the color of selection
improved new id function in cell tracking
allows selection to be set to 0 ID
automatic assign ID and link
opengl context fix for multiview
1st home commit
added manual tracking assistance option in the trace dialog. when enabled, ids can be automatically assigned and linked after each paint brush selection.
improved the manual tracking assistance
Merge branch 'master' into yong_experimental
fixed several issues of different render settings when mask and/or label are present
fixed scale bar length issue
ui tweaks for render view
fixed depth atten being disabled after settings are loaded