[Developers] remove dependency of NaNChecker from MoL

[Jian Tao]

Hi,

Currently, MoL explicit requires NaNChecker. It is better to 
remove the dependency of NaNChecker from MoL by using an alias 
function.

----------------------------------------------------
In the interface.ccl of MoL
---------------------------

#USES INCLUDE: NaNChecker.h
#################################
### Functions from NaNChecker ###
#################################

CCTK_INT FUNCTION CheckVarsForNaN \
   (CCTK_POINTER_TO_CONST IN cctkGH, \
    CCTK_INT IN report_max, \
    CCTK_STRING IN vars, \
    CCTK_STRING IN check_for, \
    CCTK_STRING IN action_if_found)

USES FUNCTION CheckVarsForNaN


In the interface.ccl of NaNChecker
----------------------------------
# Provide the function to check NaNs
CCTK_INT FUNCTION CheckVarsForNaN \
   (CCTK_POINTER_TO_CONST IN cctkGH, \
    CCTK_INT IN report_max, \
    CCTK_STRING IN vars, \
    CCTK_STRING IN check_for,
    CCTK_STRING IN action_if_found)

PROVIDES FUNCTION CheckVarsForNaN WITH NaNChecker_CheckVarsForNaN 
LANGUAGE C

Regards,
Jian