Issue125 update obsscript with sft

updated build_obs_meta_dictionary.py so that it now traps sftlf files in obs/fx/sftlf
Here gleck cedes to @durack1 and @doutriaux1 
Gleck ok with this because when not hardwired (as was previously done for test case sftlf) the sftlf files are not at the top of obs_info_dictionary.json which was the turnoff...

Updated build_obs_meta_dictionary.py ALSO now incorporates the sftlf file currently needed for the test case
(sftlf_pcmdi-metrics_fx_UKMETOFFICE-HadISST-v1-1_198002-200501-clim.nc), but test case needs to be cleaned up because directory for this file currently is: PCMDI_METRICS/test/pcmdi/obs/fx/mo/sftlf ... way messed up