use gmd:protocol WWW:LINK instead of http

This update does two things:

1) Change all gmd:protocol entries of "http" to the valid entry of "WWW:LINK". There is no "http" valid in the list of gmd:protocol valids maintained at https://github.com/OSGeo/Cat-Interop/blob/master/LinkPropertyLookupTable2.csv.

2) gmd:protocol was missing from the NCDC climate and weather toolkit. I have added this entry with a value of "WWW:LINK".
Merge pull request #2 from pacioos/patch-2

use gmd:protocol WWW:LINK instead of http