Merge pull request #174 from ahocevar/feature-events

Turning @tschaub's FeatureAgent into an event extension. r=@bartvde
Merge pull request #987 from ahocevar/google-orphaned

Vector layer duplicates when changeing to google base layer. r=@bartvde
update VERSION_NUMBER to 2.13-rc5
Geometry/ProgressiveLineString: crude support for a progressive line string

This LineString supports level of detail as does the google polyline.

Very basic support...
Geometry/ProgressiveLineString: use intersectsBounds instead of contains

Previously a line woudn't be added if both end points where outside
clip*bounds. This one checks if clip*bounds and two following points
intersects each other.
Geometry/ProgressiveLineString: respect coding style, add documentation
Geometry/ProgressiveLineString: check if all components have a assigned level of detail
Geometry/ProgressiveLineString: keep track of original indexes
Geometry/ProgressiveLineString: rename progressiveGeometries to partitionedGeometries
Geometry/ProgressiveLineString: bypass bounds extension

Gains some speed due to leaving out some error checking
(which isn't needed here, all values should be checked already)