Deprecate FilterGrid : Rename to ParamGrid

[SarthakJariwala]

The functionality currently in FilterGrid is the following - Given some image data and a function, FilterGrid allows for visualization of effect of different parameters on the image. There is no 'restriction' for the function involved to be an 'image filter' - It could be any function....So the more accuarate name would be something like :

ParamGrid : Explore the interplay between one or more parameters of a given function on input image data.

The functionality of FilterGrid would not change but only renamed to ParamGrid and the usage of FilterGrid would issue a deprecation warning.