patch for both bootstrap 2 and 3 supports

Current bootstrap-datetimepicker can't work with bootstrap3. bootstrap has changes about input group and glyphicon supports. 

Add a detection at initalization about whether bootstrap 2 or 3 style is used; based on that a slightly different html set are used: (in jade format)

// bootstrap 3
.date.datetime.input-group(style="width: 300px;")
  input(type="text",class="form-control",data-format="dd/MM/yyyy hh:mm:ss")
  span.input-group-addon.add-on
    i(data-time-icon="glyphicon-time", data-date-icon="glyphicon-calendar")

// bootstrap 2
.datetime.input-append.date
  input(data-format="dd/MM/yyyy hh:mm:ss",type="text")
  span.add-on
    i(data-time-icon="icon-time",data-date-icon="icon-calendar")