Read netCDF files

Reads netCDF data for given fields from a list of given files

Description: This function can be called with no input arguments, in which
case the inputs will be asked interactively from the user via GUI. Or, the function can be called with the name of one of its subroutines as the first argument and the required inputs of that subroutine as the following arguments. Eash of these subrountines can be used specifically to do a certain task on netCDF files. These subroutines can be called as below with their required inputs and outputs.

Subroutines: 'ncglobalattrs','findncindexes','ncseries','ncgrid'

[ncAllVars globalAttrs resol vNames XLAT XLONG]= readncfiles('ncglobalattrs', ncid)
[X_idx Y_idx pointsLatLon]= readncfiles('findncindexes', resol,XLAT,XLONG,matxls)
[ncOut]= readncfiles('ncseries',ncPath,ncFiles,vID,leveL,t,diM, tOffset,pointsLatLon)
[ncOut]=readncfiles('ncgrid',ncPath,ncFiles,vID,leveL,t,diM)

Notes:
1. This function is tested only with the WRF model's netcdf outputs.

2. The main function needs GUI so it cannot be called from Linux commandline (unless slightly modified to accept the inputs via function variable passing). However, the subroutines can be called silently without the need for GUI.