[PATCH v2] Move err/mem subroutines to separate files

[Edgar Kaziakhmedov]

As recently I've lost access to my previous e-mail, this e-mail is going to be
used. I've fixed codestyle a little bit, that's why I left this change in
the same commit message.

Also, I noticed some inconsistency in sense of codestyle, is it sort of legacy
or what?

NOTE: the previous message is wrong, it accidentally came from the old branch