Update configuration to work with test branch of POP-TRENDY

[Whyborn]

There is a branch of POP-TRENDY which has been improved to accept generic datasets and remove hidden option setting (see pull request). An updated version of the TRENDY configuration should be included to demonstrate the usage of the new namelist options and input specification.

[Whyborn]

@mcuntz both your and my PR should now be merged into the trunk. I did a quick test and it seemed to work fine. The only caveat is that on our machine, we have moved our parameter files (e.g. def_veg_params.txt, gm_LUTs) have been moved from the CABLE repository to our file system, so you'll need to adjust those targets in run_cable.sh. Let me know if there are any other issues when you test it.