text: Title: dcc.Input bug with decimal values
  Body: when using the input component with numbers and with a callback
  
      import dash
      from dash.dependencies import Input, Output
      import dash_core_components as dcc
      import dash_html_components as html
  
      app = dash.Dash()
  
      app.layout = html.Div([
          dcc.Input(placeholder='Enter a value...',
              type='number',
              value=0,
              step=0.01,
              id='input_id',
              style={'float': 'left'}),
          html.Div(id='my-div')
      ])
  
      @app.callback(
          Output(component_id='my-div', component_property='children'),
          [Input(component_id='input_id', component_property='value')]
      )
      def update_output_div(input_value):
          return 'You\'ve entered "{}"'.format(input_value)
  
      if __name__ == '__main__':
          app.run_server()
  
  
      
  Try entering decimal values with some 0s in the decimal part, for instance 0.001 or 4.1004:
  When the callback is triggered, any ending 0 will be removed preventing you to finish writing the number