vim: fix from list reformatting in search view

vim: fix from list reformatting in search view

This patch rewrites the reformatting of the from list so it shows full
capitalized names when available (without truncating them as the old code did)
and removes the pipe characters that appear between some names.

The old code appears to assume from list (the list of senders in the thread)
coming from notmuch would be e-mail addresses, but in this version it is mostly
full names. Also in this version, the names are sometimes separated by pipe
instead of comma.

For consistency with old versions, names are still truncated at the first
period. Perhaps they shouldn't be though.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>