Remove transient jsdoc dependencies

alpha9 has the dependencies fixed again, so no need to keep taffydb and
underscore around.
Make sure that projection is an ol.proj.Projection instance
Merge pull request #2321 from ahocevar/cleanup-package-json

Remove transient jsdoc dependencies
Merge pull request #2322 from ahocevar/view-projection

Make sure that projection is an ol.proj.Projection instance
Download and use new proj4js
Update externs and ol.HAVE_PROJ4JS for new proj4js API
Update API to work with custom transforms, including proj4js

All transparent proj4js handling is now in ol.proj.get, and a new
addCoordinateTransforms function makes it easy to configure custom
transform functions. ol.Proj4jsProjection is no longer needed.
Update tests
Update example to show manual proj4js configuration
Update example to show transparent proj4js integration
Use proj4.defs instead of proj4.Proj, to conform with the proj4js API
Doc changes suggested by @probins
Change dependencies to alphabetical order
Allow Proj4js to be loaded after OpenLayers
Update to use the documented Proj4js 2.2.x API