[INTERNAL] transmit used file encodings in file lists

This information can be used to display warnings if a project
contains file encodings that are not available on the remote side e.g
CP-1252 on a *NIX system.



Change-Id: I58a8a7b1f49185e2d7ffbdc31a61f4d8a0ba604c
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1396
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>