Be more robust to seeing a poptrap without a matching pushtrap

Also add more verbose logging for decode errors.

Signed-off-by: Tudor Brindus <tbrindus@janestreet.com>

Fix up some messages about sampling wiki links

Signed-off-by: Tudor Brindus <tbrindus@janestreet.com>

build: use apt-get and update beforehand

Add explicit install instructions

Move vendored libs into a vendor/ folder

...and also tell dune that that's where vendored libs lie.
Ref ocaml/opam-repository#21227

Bump owee to 0.6

Owee 0.6 has a big speedup to the ELF parsing routine, so `magic-trace`
can pop up `fzf` much quicker now.

Add a demo C# program

One more, from Christy

Allow tracing all processes when root

Closes janestreet#20.

Signed-off-by: Tudor Brindus <tbrindus@janestreet.com>