A selection of flippable glyphs.

A few glyphs in the master have been replaced with instructions on how to create them from other glyphs. The generators will need to be updated to utilize the instructions, and more glyphs need to be converted yet.
`split-char-data.pl` now resolves compose references.

Since all of the elements are already loaded at that point anyway, seemed like an appropriate place. I'll bet the result of a circular reference is just super-fun. Don't do that.
`element-to-loose-svg.pl` add ph for compose processing
Implemented `bscale` compose op.
Add ability to handle partial/nonchar glyphs.
Redefine `%` in terms of `slash` and `_perring`.

Did it to `perthousand` as well, but that should be defined in terms of `percent`, and I'm suspicious that I neglected to make the compose recursive.
Compose is now recursive.

`perthousand` is defined in terms of `percent`, which is in terms of `_perring` and `slash`.
`_todo` glyph, proto accents, more…

*   `backslash` now defined in terms of `slash`.
*   `exclamdown` and `questiondown` now defined in terms of `exclam` and `question`, respectively.
*   `nbspace` now defined in terms of `space`.
*   Several, several primitive accented glyphs have been added by composing letters with marks. They are indicated with the notation `"fix" : "above"`, which currently doesn't do anything and is only an indicator for where the position of an accent hasn't been properly set yet.
*   A `_todo` glyph is added.
*   The splitter now generates a `_todo`-based glyph for any graphic character from Windows-1252 that has not been implemented yet.
*   The splitter now maps only the earliest name for a codepoint when reversing the name-to-codepoint mapping (which is not 1:1) in order to keep the result predictable.
Add `spread` property.

Essentially a counter to the `draw` property, a line or compose item may be marked `"spread" : false`. If false, the line (for a line) or result lines (for a compose item) do not affect the containing glyph's bounding box (i.e., width) but are still drawn (unless `"draw" : false`, which is probably worthless).
Bounds calculation no longer autoincludes 0,0.

New compose ops in the works require that glyphs that float clear of the baseline not include the origin arbitrarily. Fortunately, none of the existing code appears to depend on the origin being included, so it's only thrown in if no lines are defined.
Composition transforms now in `ComposeRunner.pm`.

The original `get_compose_lines` in `element-to-loose-svg.pl` was growing into a hairy dispatch table. It is now implemented more naturally as a state object. Methods can be looked up and called by a string name, so a JSON array can easily
be converted to a call with parameter list.
Placed `anchors` in sort order.
Composer taught to use anchors.

A short sequence of compose commands can be used with anchors to properly place and center diacritics.

In this commit is an example for `idieresis`. An anchor `d-top` is specified for the dieresis (it is placed 50 below the bottom-center of the diacritic). Compose instructions are used to align the `d-top` from the dieresis with the `top` from the letter. (`top` and a few others are automatically set to bounding box edges unless specified explicitly.)
Added `aligndia` compose op.

`["aligndia","NAME"]` is a shorthand for translating the current glyph so that the target `d-NAME` is at the same coordinates as the target `NAME` from a previously drawn compose item `base`. For example, in `circumflex` we define `d-top` at 50 below the bottom center of that glyph. When composing `ecircumflex`, we include `e` and name the compose item `base`, then we include `circumflex` and use the op `["aligndia","top"]`. `d-top` of this glyph is now aligned with `top` of the base glyph.
Fixed non-reversing scale.

It looks like when `ComposeRunner` was written something went a little wrong with `_scale_about_origin`; if the scale factors were both positive or both negative, the segment points would never be added to the list of points to be modified, leaving the segments unscaled. Oops.
Added ae and oe ligatures.
Added `cent`, `copyright`, `registered`.
Add compose op `translatetoprevious`.

Like `translatefromprevious` but backwards.
Add `ordmasculine`, `ordfeminine`, `brokenbar`.
Shrunken digits, sup 1, 2, 3

Also a yet unused `_place` glyph that might be used to help place super/subscripts.