Add block amount of detail information key

Change-Id: I485c0f934e9f69b4f8ecba782cd47eb914262627
Block opacity and color are now more independent

Block opacity can be set while still showing the colormap of the data.
Block color must now be set in order to override the mapper's color map.
Only works when Interpolate Scalars Before Mapping is on and
SetColorModeToMapScalars() has been called (if you want the backface
visible).

Change-Id: I159eeeb068f1ac1fbd49eded0d0f43d6b392508d
Merge topic 'streaming-multiblock-genericio-reader' into master

b2bd40ab Block opacity and color are now more independent
2f43b031 Add block amount of detail information key