fix resize bug and support custom attributes.

resize bug:

when form field use 'col-md-x' to wrap it, resize window will have problem.

support custom attributes, for example

	$(selector).tokenfield({
	        autocomplete: {
	            source: [
				{
	            	value: 'green',
	            	label: 'green',
	            	image: 'assets/images/case-1.png'
	            },
				{
	            	value: 'red',
	            	label: 'red',
	            	image: 'assets/images/case-2.png'
	            },
				{
	            	value: 'blue',
	            	label: 'blue',
	            	image: 'assets/images/case-3.png'
	            },
	            {
	            	value: 'kl10',
	            	label: 'kl10',
	            	image: 'assets/images/avatar-32-1.png'
	            },
				{
	            	value: 'kw10',
	            	label: 'kw10',
	            	image: 'assets/images/avatar-32-2.png'
	            },
				{
	            	value: 'kx10',
	            	label: 'kx10',
	            	image: 'assets/images/avatar-32-3.png'
	            },{
	            	value: 'ww10',
	            	label: 'ww10',
	            	image: 'assets/images/avatar-34-2.png'

	            },{
	            	value: 'pv120',
	            	label: 'pv120',
	            	image: 'assets/images/avatar-34-3.png'	
	            },{
	            	value: 'gd123',
	            	label: 'gd123',
	            	image: 'assets/images/avatar-34.png'

	            }],
	            delay: 100,
	            renderItem: function(ul, item){
					return $( "<li>" )
						.append( $( "<a>" ).html( '<img src="'+ item.image +'" alt="" width="32" height="32" /> <span>' + item.label + '</span>' ) )
						.appendTo( ul );
	            }

	        },
	        showAutocompleteOnFocus: !0,
	        delimiter: [",", " ", "-", "_"],
	        template:{
	        	token: '<div class="token square" data-value="{{value}}"><span class="token-label"><img src="{{image}}" alt="{{label}}" width="20" height="20" /><span>{{label}}</span></span><a href="#" data-bind="close" class="close" tabindex="-1">×</a></div>'
	        }
	    })