fix(js): consider 0 value for `pageX`, `pageY`
fix(js): consider 0 value for `pageX`, `pageY`

* remove error message `Uncaught TypeError: Cannot read property '0' of
undefined` if mouse position X/Y is 0
* add `get_cursor_position(e, xy)` method

If you start dragging the slider and move the mouse position X/Y until
it is `0`, it is counted as falsey which means `||` in [line
49](https://github.com/zurb/foundation/blob/master/js/foundation/foundat
ion.slider.js#L49) and in [line
55](https://github.com/zurb/foundation/blob/master/js/foundation/foundat
ion.slider.js#L55) keeps going until it gets to
`e.originalEvent.touches[0].clientX/Y` where it raises an error if it
is no touch device. I changed it to explicitly checking that the values
are `undefined`.

jaylensoeur/foundation-sites-6,ibroadfo/foundation,laantorchaweb/foundation,jaylensoeur/foundation-sites-6,RichardLee1978/foundation,wikieswan/foundation,carey/foundation,r14r-work/fork_foundation_master,elkingtonmcb/foundation,vita10gy/foundation,vrkansagara/foundation,themccallister/foundation,DaSchTour/foundation-sites,ibroadfo/foundation,ucla/foundation-sites,Teino1978-Corp/Teino1978-Corp-foundation,iwikmu/foundation,lizzwestman/foundation,mbencharrada/foundation,natewiebe13/foundation-sites,IamManchanda/foundation-sites,natewiebe13/foundation-sites,carey/foundation,djlotus/foundation,robottomw/foundation,Klaudit/foundation,Mango-information-systems/foundation,atmmarketing/foundation-sites,glizer/foundation,ysalmin/foundation,abdullahsalem/foundation-sites,JihemC/Foundation-Demo,JihemC/Foundation-Demo,signal/foundation,PassKitInc/foundation-sites,anbestephen/foundation,yohio/foundation-sites-6,dragthor/foundation-sites,jeromelebleu/foundation-sites,hummingbird-me/foundation-sites-6,andycochran/foundation-sites,barnyp/foundation,celsoyh/foundation,oller/foundation,anbestephen/foundation,JihemC/Foundation-Demo,DouglasAllen/css-foundation,ioanok/foundation,themccallister/foundation,Larzans/foundation,PassKitInc/foundation-sites,lizzwestman/foundation,vita10gy/foundation,BerndtGroup/TBG-foundation-sites,socketz/foundation-multilevel-offcanvas,pauleds/foundation,laantorchaweb/foundation,youprofit/foundation,r14r/fork_foundation_master,marcosvicente/foundation,RichardLee1978/foundation,leo-guinan/foundation,walbo/foundation,gnepal7/foundation,Owlbertz/foundation,oller/foundation,djlotus/foundation,mbencharrada/foundation,robottomw/foundation,jxnblk/foundation,joe-watkins/foundation,zurb/foundation-sites,jamesstoneco/foundation-sites,IamManchanda/foundation-sites,a-dg/foundation,celsoyh/foundation,claytonrodgers/foundation,sitexa/foundation,jxnblk/foundation,claytonrodgers/foundation,brettsmason/foundation-sites,celsoyh/foundation,r14r/fork_foundation_master,gnepal7/foundation,JihemC/Foundation-Demo,karland/foundation-sites,Teino1978-Corp/Teino1978-Corp-foundation,BerndtGroup/TBG-foundation-sites,jamesstoneco/foundation-sites,DaSchTour/foundation-sites,lizzwestman/foundation,youprofit/foundation,Iamronan/foundation,RichardLee1978/foundation,birthdayalex/foundation,Mango-information-systems/foundation,dragthor/foundation-sites,karland/foundation-sites,themccallister/foundation,jxnblk/foundation,Larzans/foundation,Iamronan/foundation,youprofit/foundation,marcosvicente/foundation,samuelmc/foundation-sites,joe-watkins/foundation,pauleds/foundation,mbencharrada/foundation,designerno1/foundation-sites,sashaegorov/foundation-sites,DouglasAllen/css-foundation,sethkane/foundation-sites,jlegendary/foundation,NeonWilderness/foundation,zurb/foundation,marcosvicente/foundation,joe-watkins/foundation,karland/foundation-sites,ysalmin/foundation,Mango-information-systems/foundation,djlotus/foundation,joe-watkins/foundation,NeonWilderness/foundation,stanwmusic/foundation,PassKitInc/foundation-sites,jxnblk/foundation,ibroadfo/foundation,laantorchaweb/foundation,claytonrodgers/foundation,anbestephen/foundation,Owlbertz/foundation,mbarlock/foundation,getoutfitted/reaction-foundation-theme,claytonrodgers/foundation,asommer70/foundation,advisorwebsites/foundation-sites-6,adstyles/foundation,Teino1978-Corp/Teino1978-Corp-foundation,walbo/foundation,atmmarketing/foundation-sites,a-dg/foundation,mbarlock/foundation,wikieswan/foundation,jlegendary/foundation,vrkansagara/foundation,celsoyh/foundation,dimamedia/foundation-6-sites-simple-scss-and-js,ysalmin/foundation,zurb/foundation,abdullahsalem/foundation-sites,zurb/foundation-sites-6,zurb/foundation,sashaegorov/foundation-sites,NeonWilderness/foundation,ysalmin/foundation,denisahac/foundation-sites,r14r-work/fork_foundation_master,dimamedia/foundation-6-sites-simple-scss-and-js,atmmarketing/foundation-sites,sethkane/foundation-sites,aoimedia/foundation,socketz/foundation-multilevel-offcanvas,gnepal7/foundation,signal/foundation,barnyp/foundation,elkingtonmcb/foundation,pauleds/foundation,glunco/foundation,iwikmu/foundation,hummingbird-me/foundation-sites-6,r14r/fork_foundation_master,Owlbertz/foundation,glizer/foundation,mbarlock/foundation,stanwmusic/foundation,MarcGuay/foundation,abdullahsalem/foundation-sites,leo-guinan/foundation,natewiebe13/foundation-sites,labr1005/foundation,marcosvicente/foundation,pdeffendol/foundation,r14r/fork_foundation_master,glunco/foundation,adstyles/foundation,wikieswan/foundation,robottomw/foundation,glunco/foundation,Larzans/foundation,labr1005/foundation,pdeffendol/foundation,jaylensoeur/foundation-sites-6,zurb/foundation-sites,mbarlock/foundation,zurb/foundation-sites,adstyles/foundation,andycochran/foundation-sites,BerndtGroup/TBG-foundation-sites,vrkansagara/foundation,NeonWilderness/foundation,pauleds/foundation,vrkansagara/foundation,oller/foundation,asommer70/foundation,pdeffendol/foundation,iwikmu/foundation,glunco/foundation,sashaegorov/foundation-sites,colin-marshall/foundation-sites,labr1005/foundation,Klaudit/foundation,MarcGuay/foundation,stanwmusic/foundation,birthdayalex/foundation,designerno1/foundation-sites,stanwmusic/foundation,anbestephen/foundation,Klaudit/foundation,jamesstoneco/foundation-sites,ioanok/foundation,laantorchaweb/foundation,lizzwestman/foundation,carey/foundation,sitexa/foundation,robottomw/foundation,a-dg/foundation,birthdayalex/foundation,getoutfitted/reaction-foundation-theme,mbencharrada/foundation,glizer/foundation,Larzans/foundation,ucla/foundation-sites,colin-marshall/foundation-sites,denisahac/foundation-sites,elkingtonmcb/foundation,zurb/foundation-sites-6,r14r-work/fork_foundation_master,ioanok/foundation,barnyp/foundation,DouglasAllen/css-foundation,samuelmc/foundation-sites,wikieswan/foundation,elkingtonmcb/foundation,Teino1978-Corp/Teino1978-Corp-foundation,jlegendary/foundation,jeromelebleu/foundation-sites,MarcGuay/foundation,getoutfitted/reaction-foundation-theme,leo-guinan/foundation,barnyp/foundation,aoimedia/foundation,denisahac/foundation-sites,yohio/foundation-sites-6,sethkane/foundation-sites,RichardLee1978/foundation,socketz/foundation-multilevel-offcanvas,adstyles/foundation,jlegendary/foundation,MarcGuay/foundation,dragthor/foundation-sites,advisorwebsites/foundation-sites-6,colin-marshall/foundation-sites,jeromelebleu/foundation-sites,Iamronan/foundation,designerno1/foundation-sites,DouglasAllen/css-foundation,samuelmc/foundation-sites,glizer/foundation,a-dg/foundation,birthdayalex/foundation,walbo/foundation,leo-guinan/foundation,walbo/foundation,brettsmason/foundation-sites,asommer70/foundation,vita10gy/foundation,asommer70/foundation,ucla/foundation-sites,ibroadfo/foundation,signal/foundation,sitexa/foundation,carey/foundation,gnepal7/foundation,aoimedia/foundation,vita10gy/foundation,brettsmason/foundation-sites,signal/foundation,djlotus/foundation,Owlbertz/foundation,andycochran/foundation-sites,IamManchanda/foundation-sites,youprofit/foundation,Klaudit/foundation,sitexa/foundation,labr1005/foundation,iwikmu/foundation,r14r-work/fork_foundation_master,pdeffendol/foundation