Add all_emoji and emoji_sort options to generate_emoji_html.
Add all_emoji and emoji_sort options to generate_emoji_html.

By default, the list of emoji sequences is based on the union of
the sequences encoded in the image file names for all the directories
(or the first directory if --limit was set).  The --all_emoji option
uses the emoji sequences from nototools/unicode_data instead.

By default, the list of emoji sequences is in unicode codepoint order.
The --emoji_sort option uses the emoji sequence sort order from
nototools/unicode_data instead.

Along with this, the ordered list of sequences becomes an argument to
write_html_page, which it should have been all along.

googlei18n/noto-emoji,radiocane/noto-emoji,moyogo/noto-emoji,googlefonts/noto-emoji,googlei18n/noto-emoji,dougfelt/noto-emoji,radiocane/noto-emoji,mxalbert1996/emojione-android,julroy67/noto-emoji,moyogo/noto-emoji,julroy67/noto-emoji,googlefonts/noto-emoji,dougfelt/noto-emoji,googlefonts/noto-emoji,dougfelt/noto-emoji,googlei18n/noto-emoji