Render ambiguous width emoji always full-width

[tompng]

Note: This ambiguous is not about EastAsianWidth.

Width of some emoji such as 🇯🇵(Flag emoji) and ©️(Extended_Pictographic + Variation_Selector_16) are ambiguous.
It depends on terminal emulator and its configuration.
For example, iTerm has "Flag emoji render full-width: Yes/No" and "Support variation selector 16 making emoji fullwidth" configuration.

This pull request renders these ambiguous width emoji always in full-width by this step.

1. Render " " to clear text and background
2. Render ambiguous emoji. Actual rendered width is uncontrollable.
3. Move cursor as if it was rendered in full-width.

Here's an example.

# Width of ©️ and 🇯🇵 depends on environment
print "\e[1G😀😀©️🇯🇵😀"

# Render ©️ and 🇯🇵 always in full-width
print "\e[40m0123456789\e[m" # This text and background needs to be cleared
print "\e[1G😀😀\e[5G  \e[5G©️\e[7G  \e[7G🇯🇵\e[9G😀"