Turn off all modules by default

Rely on dependencies to turn on the modules require to support
CDAT and VisTrails.
CDAT_USE_SYSTEM_pkgconfig => CDAT_USE_SYSTEM_PKGCONFIG

The package name should be uppercase.
VisTrails needs Cython
Include Python package before VTK
SCIPY is needed by CDAT
Pass Python version to VTK build
Pass system lapack and blas directories to SCIPY
Correct case of VTK_deps
Only enable the VTK modules we need
Fixed bug related to package not getting enabled at the secondary level

If package A dependent on B and B if OFF, B will be turned ON if
A is ON but now we to have to recursively turn ON the dependencies
of B as well
Genutil requires udunits
Turn Wget to SYSTEM by default
Clean up cmake logic related to ESGF option
Enabled scipy as needed by vistrails
Added CDAT_BUILD_FULL option, used it to change dependencies of ipython, reinstaured CDAT_BUILD_ESGF
add the option in wrong order
Using CMake style variable name
Force cache states or else it won't be set right after first time
Removed debug messages