move imsgev & co to their own file This avoids bringing the dependency on ev on telescope-identity(1) and the tests as well.

convert telescope to use ev instead of libevent libevent is a very cool library, I like the APIs and enjoy using it. However, telescope is not as large and doesn't have as many file descriptor, so libevent is quite ``too big'' for our needs. ev started as a small event loop on top of poll(2) for amused, and can be used here too, it just needed to grow the ability to handle several timers, as we need quite some on telescope (in fact, we use more timers than fds!)

move tofu declarations to their own header While here replace GEMINI_URL_LEN with TOFU_URL_MAX_LEN to avoid a dependency on telescope.h. Ideally, we should move this stuff to another header that comes with less dependencies.

first draft of client certificate support At the moment telescope loads a mapping host:port/path -> certificate from a file and always uses it, no ways to change it, use a temporary one, generate a new one, etc are provided yet. The format of ~/.telescope/certs/certs is host port path certificate file name where the certificate file name is the name of a file inside ~/.telescope/certs. ~/.telescope/certs/ is ~/.local/share/telescope/ when using XDG.

rework the history management It was a huge pile of spaghetti with useless utility functions and lots of code reaching into the "data structure" (if you can call it so) to do stuff. Instead, provide a "module" with a clean interface and noone reaching in the insides.

don't allow the history to grow too much + save_session refactoring add a mechanism that will signal a regeneration of the history file once it reaches the 150% of the HISTORY_CAP. while here refactor save_session, now it's somewhat readable.

unbreak history file I can't use the ""generate temp file + rename" trick used for the session file, because I only add items that are not "dirty". the history-on-disk things needs some improvements, mostly to limitate the size of the file, but for the time being unbreak it!

move load session stuff to session.c

generate session/history_file atomically if an i/o error occurs while writing those files, they may end up being corrupted or truncated. Use the approach already used for tofu, write a temp file and rename(2) it to the correct position.

merge the fs into the ui process The previous separation between the fs and ui process wasn't that good. The idea was to have a `ui' process tightly sandboxed, but it was a lie actually. `ui' was one imsg away from making internet connections and accessing data on the disk, so it wasn't really limited in (almost) any way. Furthermore, having to serialize data to/from the fs proc started to become not really maneagable. As a first step to fix this situation, join the fs and ui process.

persist list of visited URLs to the disk Persist a generalized history of visited URL in history_file and try to keep it in sync during telescope usage and shutdown.

initialize each tab loadingev timer event found on freebsd: closing a tab caused the message "event_pending: event has no event_base set" to be print.

doesn't need parser.h anymore

move TAB_LAZY flipping from switch_to_tab in load_url load_url needs to know when a tab passes from lazy to not lazy to correctly saves the scrolling position (see follow-up commit.)

save and restore scroll position Save the offset to the first and current line of the buffers and restore it when the page is loaded. This restores almost the exact viewport: we save the offset of the *real* line in the document, but they get wrapped before being displayed, so the actual restored position may be slightly above from the original one (think of a long paragraph that gets wrapped over multiple visual lines.) In practice, this isn't a drawback but only an improvement over the current behaviour. In the future we could save also the offset *inside* the line, to restore the exact position, but that felt unnecessary for now. Persisting the postion on the session file ensures that even when re-opening telescope the scroll position is correct. There are some very active pages, such as antenna or other aggregator, where this feature doesn't really work well if you re-open the page after a while, since new links are available, but otherwise is a god sent! See also github issue #1