Fix gl plane feature

Fixed GL plane feature not respecting the GCS along with some other fixes. 
This behavior is inconsistent with coordinate conversion in `osmLayer`.  See here: https://github.com/OpenGeoscience/geojs/blob/fix_gl_plane_feature/testing/test-cases/jasmine-tests/osmProjection.js#L48

Is there a reason `osmLayer` is handling projections by itself rather than deferring to `geo.transform`?