Update projections to use the proj4 plugin

[mlucas17]

It would be nice when we redo our projections if we worked in a proj4 plugin. That's the projection code the rest (Europeans, Candians, ...) of the world use.

[gpotts]

This will be used as a fallback projection creator if any of the Geotrans projectors are not found. proj4 is a defacto standard library that has a number of map projections available. If we support proj4 and also support their projection string definition this will allow OSSIM to be used in a much wider environment.