fix cleanUrl regex so that spaces in folder names arent trimmed

[jgravois]

i noticed this morning that L.Util.cleanUrl incorrectly trims spaces inside url folder names.

L.esri.Util.cleanUrl('http://utility.arcgisonline.com/arcgis/rest/services/Utilities/PrintingTools/GPServer/Export Web Map Task/execute  ');
//Export Web Map Task becomes ExportWebMapTask (and induces 400 errors in requests)
>>"http://utility.arcgisonline.com/arcgis/rest/services/Utilities/PrintingTools/GPServer/ExportWebMapTask/execute/"

i've fixed using another regex i found on the internet.

[patrickarlt]

@jgravois I think you could replace using 2 calls to replace with this.

url.replace(/^\s+|\s+$|\A\s+|\s+\z/g, '');

It's a little silly but it should only match whitespace at the start/end of the string/line. Here is a link to test it http://rubular.com/r/PgHbPEL6EO

[jgravois]

sweet. fixed, ran grunt tests and confirmed manually everything was good, rebased and merging now.