Split visad module

[lesserwhirls]

Related to #105

Split the visad module into the following new modules:

• mcidas/gempak
• visad5

The dividing line here is that mcidas and gempak IOSPs depend very little on visad.jar, and can pull in the necessary code to keep them working. the vis5d IOSP depends heavily on visad.jar, so it can be split off into its own module to allow uses to pull in that dependency or not.

[JohnLCaron]

Vis5D is not currently loaded into the IOSPs.
So the only possible use is someone calling it directly, maybe the IDV?
Would be easy to check by grepping their code.

[lesserwhirls]

I don't see Vis5DIosp used anywhere in the IDV. I'll ask our committees in a few weeks to see if they know of anyone using that capability, and I'll check the download metrics on visadCdm.jar from nexus to get an idea of overall usage.

[lesserwhirls]

Closed by #123