based on Ferrari's method (whence its name).
     Input: the c[] coefficients in
         X^4 + c[0] X^3 + c[1] X^2 + c[2] X + c[3],
     an array of reals, and an array of integers.
     The routine fills these arrays with the real roots (when they exist)
     and their respective multiplicities, and returns the number of roots.

ENH: VTK_TCL_HOME is the path where pkgIndex.tcl can be found when it is post-fixed with one of the configuration types (Debug, Release, etc.), *if any*.

BUG: VTK_TCL_HOME is only used for external config purposes, but is not set correctly in the build tree, it should point to VTK_BINARY_DIR, not VTK_SOURCE_DIR, since the packages are actually being configured in the bin dir

ENH: added fast path calculation with threading for gradients in the fixed point ray caster, added progress and tied it into GUI in KWVolumeWidget

BUG: Fixes Bug #2312 - SNL: Better error handling when out of memory without reliance on C++ exceptions. The ouput window throws error and warning events which can be handled. The event handler on the server side processmodule parses the text to check for out of memory errors and reports them accordingly.