wcstools: Add libwcs subport

[ryandesign (Ryan Carsten Schmidt)]

funtools has a bundled copy of libwcs but it is outdated, and generally we want to use MacPorts-provided copies of libraries anyway, but we don't appear to have a port for libwcs yet, and the wcstools port doesn't install libwcs.

We do have a wcslib port but that appears to be a different software package.

I suggest that a libwcs subport of the wcstools port should be created.