use iri_setport instead of reaching into the struct iri

convert the remainig uses of phos_uri to the iri API

move cwd to fs.c

apply load-url-use-heuristic for command line arguments too This semplifies a bit the handling. humanify_url() now takes the base URL which we can then use when not using the heuristics. Command-line arguments now take an implicit base of <file://$PWD/> when the heuristics are disabled, so that foo.gmi resolves to the local file even without <./>. See github issue #10.

convert humanify_url to iri APIs

make do_load_url and friends return void The 0/1 difference was once important since it would give the caller an idea whether the page was loaded immediately or asynchronously. This doesn't matter anymore. Furthermore, this whole family of function can't really fail (as telescope doesn't handle memory allocation failures gracefully.)

s/IMSG_GET_RAW/IMSG_GET and gc unused IMSG_GET_FILE

fix regression: open the url given on the command line was broken after the fs/ui merge

unbreak downloads the recent commit to rework handle_save_page_path changed the tab id *before* setting it to the download, so the ui and net process went out of sync and downloads hanged.

drop the `buffer' flag for enqueue_download it's unused as write_buffer now writes a buffer to the disk.

fix handle_save_page_path there's no need to handle the buffer case, which is now handled directly by write_page. While here fix an issue if the open fails: we still need to stop the tab!

replace has_prefix with strncmp

move load session stuff to session.c

merge update_cert and tofu_update into tofu_update_persist

merge tofu_add and save_cert into tofu_save