Correct/improve dragbox docs
Add @todo API and describe ol.geom.Geometry funcs

The `clone()`, `getSimplifiedGeometry()` and `getType()` methods are all
base class methods documented in subclasses.  They should appear in
ol.geom.Geometry in the API docs as well.
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
Merge pull request #2204 from probins/dragbox

Correct/improve dragbox docs
Document that feature properties are set as object properties
Document that layer options are set as object properties
Merge pull request #2298 from probins/props

Document that options in layers and properties in features are set as object properties
Merge pull request #2177 from pagameba/geometry-api

Add @todo api and describe ol.geom.Geometry funcs
Add proj4 to package.json