drop maintainer

Hi all,

I haven't been diligent lately and as I'm starting law school in the
fall it's not likely to improve much so with regret I feel obligated to
drop MAINTAINER on these ports

sysutils/lr
sysutils/xe
textproc/pandoc

Sorry for lack of diff to this effect. I will hopefully still fiddle
with ports as able, I just don't want to hold myself out as being able
to do timely maintenance.

Thank you,
Evan