minor style change
Minor alignment issue with input box
Calculate width of input element using pseudo element

A pseudo element is created to which placeholder value is assigned using which approximate width of the input box is calculated. As soon as width is calculated, pseudo element is deleted immediately.
Added support for enter key based tag creation

Options such as 'addOnComma' and 'addOnReturn' are introduced which can be used to decide on which key press tag will be created. By default both options are set to true