Typos and update to the PKGBUILD

Minor man page changes

Handle http errors on HEAD in get_mime_type

Add comment about the url replacement bug

Add message about non working parameter interpolation

Fix the project link in the man pages

Update the TODO file

Add variable interpolation in commands

WIP: add variables in handler's exec

Add caveat about non existant dir in path

Compress the manpages after generating them

Fixes to the README

Properly handle tildes in URIs (for file paths)

Correctly detach the child process + new log level

Using syscall.ForkExec instead of exec.Command properly detach when the
option asks it to

Typo fixes + pgk version bump for PGKBUILD

Update to the man.5 page

Small changes to some log messages

Also update the TODO

Add 2 mutating filters: c_includes and man

These filters mutate the URI so it can be handled by the programs that
usualy open them

Add a notification commad option

This option is used to show errors if a handler command can not be
found. Could also be used in more parts of the code to signal errors to
the user.

Go mod tidy