Adds support fortext presentation sequences.

Just as emoji presentation sequences can transform non-emoji characters into emoji (potentially increasing their width),
text presentation sequences can transform emoji into non-emoji (potentially decreasing their width). For example,U+1F004 MAHJONG TILE RED DRAGON has emoji presentation by default, but with a text presentation selector it should become narrow like all the other Mahjong tile characters.

Some default-emoji characters should clearly remain wide even in text presentation, however.U+1F21A SQUARED CJK UNIFIED IDEOGRAPH-7121 is one such example.

What does Unicode say about all this? Thelatest draft of UAX 16 says:

In some cases, variation sequences have been defined that request a character to be displayed as wide or narrow. These variation sequences are defined in StandardizedVariants.txt [StandardizedVariants] in the [UCD], but they are identified via the description of the intended glyph style and not via a formal property of the variation sequence. Nevertheless, the presence of the respective variation selector should be considered a sufficient condition to resolve ambiguous width to either wide or narrow [...]

In other words, we're on our own. I've chosen to make default-emoji in theEnclosed Ideographic Supplement block remain wide, and have all others become ambiguous-width.

Adds 532 bytes of static data.