Fixed thermal wind calculation to some extent

Signed-off-by: deepak <dpak.cherian@gmail.com>
Major changes to make code more general. Almost done with getting thermal wind to work. Working on zeta field now.

Signed-off-by: deepak <dpak.cherian@gmail.com>
Finished zeta calculation and fixed PV calculation.

Signed-off-by: deepak <dpak.cherian@gmail.com>