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.
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
Pass tolerance to ReplayGroup

The tolerance instead of the squared tolerance must be passed to the ReplayGroup constructor.
Merge pull request #2325 from elemoine/imagevector

Pass tolerance to ReplayGroup
Change examples/vector-osm to use transformExtent
Merge pull request #2326 from probins/osmxml

Change examples/vector-osm to use transformExtent
Allow addFeaturesInternal to add multiple features lacking an id