Expandable Utterance in Channel Config

[rgauss]

From pull request #9:

Would be nice to be able to provide expandable utterance_name, i.e.

utterance_name: 'watch {NGC|National Geographics}'

this generates

WatchTivoWatch{NGC|National Geographics} to watch NGC
WatchTivoWatch{NGC|National Geographics} watch NGC
WatchTivoWatch{NGC|National Geographics} to watch National Geographics
WatchTivoWatch{NGC|National Geographics} watch National Geographics

which is not accepted by amazon.

The current code should already remove the spaces, but could easily convert the curly braces and pipes to something acceptable as an intent name:

WatchTivoWatchNGC_NationalGeographics to watch NGC

There would still be the problem of the responses being unintelligible.

Perhaps an optional response could be used if present in the channel configuration, otherwise use the first variation in the utterance expansion.