Improve docs for style
Merge pull request #2481 from probins/styledoc

Improve docs for style
Correct wrong docs for LinearRing
Properly clear features in ol.source.ServerVector#clear
Restore context opacity after drawing layers

Closes #2455
Merge pull request #2455 from fredj/2455

Opacity of last layer is used in postcompose drawing
Merge pull request #2496 from probins/linear

Correct wrong docs for LinearRing.

Closes #2495.
Merge pull request #2499 from fredj/2294

Properly clear features in ol.source.ServerVector#clear
Use definition with 7-parameter transform for EPSG:21781
Merge pull request #2498 from ahocevar/custom-def

Unprecise transormation used in example
Replace multiple placeholder occurrences in templates
Merge pull request #2497 from ahocevar/greedy-template

TileUrlFunction only replaces first instance of placeholder variables
Add new olx.format.KMLOptions#extractStyles property