base underline style and color extension support

[rysson]

No bug found for one year, I create PR.

Support for underline style and color extension

<ESC>[4:0m  # no underline
<ESC>[4:1m  # straight underline
<ESC>[4:2m  # double underline
<ESC>[4:3m  # curly underline
<ESC>[4:4m  # dotted underline
<ESC>[4:5m  # dashed underline
<ESC>[4m    # straight underline (for backwards compat)
<ESC>[24m   # no underline (for backwards compat)

<ESC>[58...m   # set the underline color
<ESC>[59m      # reset the underline color