Improved params checking in ReadQethAttributes.

Simple forgotten commit from pre-ruby era.
Merge remote-tracking branch 'upstream/master'
Added comments for LanItems::Read and ::ReadHw
LanItems is able to return names of all known netcards. bnc#578787

It returns really all netcards available and/or configured in the
system. It used to return configured only.
Created infrastructure and first test in Ruby / Minitest

Duplicates test for querying netcard device names.
Updated .gitignore
Updated changelog

Conflicts:
	VERSION
	package/yast2-network.changes
Merge pull request #110 from mchf/bnc578787-GetAllInterfaces

Extended LanItems API - can request list of all netcard names.