hook iri.[ch] into the build

draft of the new iri parser for the moment is just a URI (RFC3986) parser, and not even a complete one, but I like it much more than phos_uri. It's more gentle in the memory consumption and has a cleaner API. It's not complete, some parts are still stubbed or completely to implement, but it's the start. It compiles. Step-by-step integration of it in telescope and testing will come later.

make clear to which struct every L_* flag is supposed to belong to

start to refactor the rendering Previously each vline (visual line) had a full copy of its associated string, this changes it so it only slices a part of the parent line. Reduces significantly the memory usage. This actually worsen the emojify-link glitch reported by Freezr after the some recent refactoring in the wrapping code. Not a big deal since I'm about to restructure the whole rendering bit by bit (hopefully!)

make phos_uri compile with -Werror temporary band-aid until i find the time to rewrite this stuff...

add the libgrapheme makefile was forgotten during import because of the .gitignore. Reported by Freezr, thank you!

mention libgrapheme in the README.md while here collect the links at the end.

use pkg-config for libgrapheme

bundle libgrapheme 2.0.2 in case it's not available

account for the prefix width when wrapping lines

remove wrap_one, use an extra parameter for wrap_text

use libgrapheme for text reflowing unlike the previous hack, libgrapheme is UNICODE 15.0 compliant (at the time of writing) and provides some nice API. While here, drop the hard wrap method for preformatted blocks: always use the normal wrapping. Since libgrapheme is not yet widely available, future commits will probably add a bundled version to ease packaging. I'll also start to replace various home-grown UNICODE/utf8 handling routines with functions from libgrapheme.

add ignore entries for the site-generated files

update the logo; from freezr!

link freezr' post about the telescope logo