tgt: update to 1.0.48 and add all stuff announced in the the previous commit

Signed-off-by: Maxim Storchak <m.storchak@gmail.com>
tgt: change example network

Signed-off-by: Maxim Storchak <m.storchak@gmail.com>
Merge pull request #9 from mstorchak/tgt_update

update tgt to 1.0.48, add previously announced stuff