-lm silently wins fight with -jsgf

[gitfoxi]

I guess it doesn't make sense to use both Language model and a grammar. It would be nice if pocketsphinx just refused to do this rather than silently letting the language model win. It's a trap for young players.

[dhdaines]

The logic behind all these command line arguments is sick and twisted and not documented, which is a problem. You can sort of see how it works here: https://github.com/cmusphinx/pocketsphinx/blob/master/src/pocketsphinx.c#L317

As you say, in reality, we should just require the user to select one and only one of -lm, -kws, -fsg, -jsgf, etc (there are lots of them). I'll fix this for the upcoming release (this week I hope).