Allow null GeoJSON geometries.

This change checks if a geometry/ies in GeoJSON are set as null, in
which case it will skip it.
This modifies the Android WebView phantom click workaround.
Previously it was blocking when an element had multiple click listeners
because those events were fired rapidly. Since Android fires its second
click at approximately 300ms after the first we do a check to make sure
that at least 100ms has elapsed but not more than 400ms.
Merge pull request #1237 from Felixls/patch-1

Update build/build.js
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
fix iOS vectir zoom anim regression, close #1259
update build
update license year
update link to the new repo location
Add missing "be" to CONTRIBUTING.md
Merge pull request #1265 from krekoten/contributing-fix

Add missing "be" to CONTRIBUTING.md