Change marker click tracking. Only care if the map has been dragged if we are not draggable.

If we are draggable and we get a possible click then we don't need to care if the map was dragged as we would have been handling the drag.

Fixes #1223
handle existing query strings for WMS urls , #973
Semicolons in spec
cleanup to match convention
whitespace for hash
Allow null GeoJSON geometries.

This change checks if a geometry/ies in GeoJSON are set as null, in
which case it will skip it.
handling no existingUrl scenario
Merge pull request #1231 from snkashis/fix_wms_params

handle existing query strings for WMS urls , #973
pass the clicked obj, not the map.
Merge pull request #1243 from snkashis/fix_canvas_ref

Handling clicks on paths with L_PREFER_CANVAS, #1215
Merge pull request #1244 from danzel/fix-events

Change marker click tracking. Only care if the map has been dragged if we are not draggable.
Re-add L.Browser.ie as it is used in debug\vector\geojson.html(113). Fixes #1242
Simplifying condition for null geojson geometries.

Used feedback from @mourner to make the change from the pull request
#1240
Merge pull request #1240 from brianherbert/allow-null-geojson

Allow null GeoJSON geometries.
Merge pull request #1245 from danzel/ie

Re-add L.Browser.ie as it is used in debug\vector\geojson.html(113). 
Fix issue 1226: IE10 "Invalid argument" error in version 0.5 defining retina
https://github.com/CloudMade/Leaflet/issues/1226

Credit to dreamfall for the fix.
Merge pull request #1251 from Guiswa/dev/guiswa/issue1226

Fix issue 1226: IE10 "Invalid argument" error in version 0.5 defining retina
Initial version of of ImageOverlay.Canvas layer