iri: always output file:// urls with the `//' separator

iri: rework iri_unparse() I'm not actually pround of the %s%s%s%s%s%s... etc, but it works fine. There's no need to do further escaping here, since consuming code is not supposed to reach inside the iri struct. It'll be made opaque maybe in the future.

fix handling of gopher selectors Much of telescope works in terms of URI, so we convert each gopher link to an URI. However, we didn't urlencode the path parameter, thus failing on every link that contains spaces or similar invalid (in URI paths) characters. Issue reported by hryjksn on github, thanks! https://github.com/omar-polo/telescope/issues/14

iri: fix parse_path_absolute with path being "/" it was mis-parsed as "" causing failures when resolving a relative URI.

iri: add iri_setport() takes a string because the internals of telescope makes it easier to use if a string.

iri_setquery: avoid needless else block

add missing #include "compat.h"

iri: refactor parse_{query,fragment} into a single function

iri: copy portstr too

iri: make mergepath take a buffer and strings, not the iri pointers

iri: change remove_dot_segmens to take a buffer instead of an iri

iri: zero iri_flags before parsing

iri: use a temp buffer for %enc in iri_setquery

iri: implement iri_setquery

iri: fix port parsing

iri: support framents and enable fragments tests

iri: rewrite remove_dot_segments to be clearer the previous version was straight out RFC3986 (more or less, it had a bug I didn't spot), but it's ugly and extremely long. Rewrite it to be somewhat inspired by canonpath (from kern_pledge.c) and way simpler. There are some small differences in how UNIX paths and URLs paths are canonized (in UNIX path you don't care too much of a trailing '/', in URLs you do.) The new code is more clear and passes all the tests in RFC3986, so I'm calling it a win.

iri: fix remove_dot_segments algorithm i've misread the description in the RFC; we should copy up to, but not including, the next '/' at the end and manually inject some '/' in some other cases.

iri: fix remove_dot_segments: should copy until (including) "/"

iri: fix typo: should check the first two characters, not three

iri: fix path check path should *start* with "/" to enter that branch, not be exactly "/".

iri: fix logic in iri_unparse make sure path starts with "/" only when there's an authority part, not when it's not there!

iri: drop extraneous cpfields(IH_QUERY)

iri: set some flags as defined only when actually copying

iri: draft iri_unparse