Add Unicode properties of East Asian Width

[aycabta]

This Pull Request adds Unicode properties about East Asian Width. Supports only full name because some aliases are duplicated, such as N.

In Unicode 10.0.0, this adds below:

• Ambiguous
• Fullwidth
• Halfwidth
• Neutral
• Narrow
• Wide

This Pull Request doesn't contain update files because those files depend on https://github.com/k-takata/Onigmo/pull/101.

For reference, Perl's regular expression supports East_Asian_Width: * type Unicode property like General_Category: *.

ref. https://bugs.ruby-lang.org/issues/14618

[codecov-io]

Codecov Report

Merging #102 into master will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #102   +/-   ##
=======================================
  Coverage   82.86%   82.86%           
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  Files          62       62           
  Lines       12827    12827           
=======================================
  Hits        10629    10629           
  Misses       2198     2198

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[aycabta]

@k-takata How is this?

[nurse]

I object this because width information is not useful in real world. For example recently added emojis are specified as "Narrow", but they are expected to be showed as fullwidth on Japanese environment.