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