added support for "opaque" networking

in preparation for zerovm interface v2.0 added support for opaque network handles
although the semantic meaning of handle is just random string the current mask is as following:

    <cluster id>-<source node id>-<dest node id>
Merge pull request #46 from pkit/opaque

added support for "opaque" networking
readme: create a proper Markdown heading
configparser: fixed indentation
proxyquery: fixed long line
gitignore: add auto-generated cover directory
Merge pull request #47 from mgeisler/small-fixes

Small fixes
fix #48 now mock correctly handles strange paths

if std device path is not a real file mock was creating that file on host fs
rerouted such files to `/dev/null`
Merge pull request #49 from pkit/tests_fixes

fix #48 now mock correctly handles strange paths