more complex file name

[ShervanGharari]

Currently, the remapped output nc files are named using the case name and an extension of starting date and time. This may result in nc files with a similar starting date and time to be overwritten during remapping. The following will be added to the code:

1. Make sure the input source nc files have a unique name even if they are located in different folders.
2. Use the original file name for the remapped file with remapped extension
3. include the source nc file name (and path) in the global attribute of remapped nc file.

[ShervanGharari]

Version 2 has a more complex file name. It keeps the original file name with the prefix of the case name and remapped. This will help remap multiple datasets such as CMIP6 bias-corrected data from various models.