mgmt: added subscription-based configuration file parser

Modules subscribe to configuration sections they are interested
in by name and provide a callback function. After parsing
the configuration file, ConfigFile will iterate through the
top level tree and invoke all subscribed callbacks for each
section it comes across.

ConfigFile has no concept of the specific tags or structure of the file
other than there being a single root tag (not a specific name) under which
all sections fall.

refs: #1120

Change-Id: Ic06fbdc85a9ac9740d46a6c2457ff5a9bd38e8a5
face: Fix bug with EventEmitter usage

Change-Id: If940c42490f63976611659677b9e2cb899562e8b
face: Small issue with TcpChannelFactory (error from gcc-4.2.1)

Change-Id: I5ddef68db85928383b962ac56ed454d69dbdf3bc