SVG: Permit 'e' to appear in SVG font glyph paths

SVG: Permit 'e' to appear in SVG font glyph paths

The definition of 'glyph-path-regexp' will only match a <path d="...">
element if the contents of the 'd' attribute do not include the letter
e. But the SVG spec permits coordinates to be given in C-style
exponential notation such as 9.8e-5. If a glyph in an SVG font uses
that ability, extract-glyph will fail, and the glyph will be silently
omitted from the output file.

by Simon Tatham <anakin@pobox.com>

Follow-up: Also allow '+Aa,' in SVG path descriptions

See https://www.w3.org/TR/2011/REC-SVG11-20110816/paths.html#PathDataBNF
Note that - must be first in the character class or it will specify
a range of characters (as the first version of this patch did).

[lemzwerg, 2020-02-21 16:14:21]

LGTM