Implementing a callback when the hotword is detected while using snowboy

[palikar]

I made the suggestion in #380 . This is the implementation and it seems to work ok.

I also made the change suggested by #306 addressing #312 . I was not able to run examples without this change.

[wibimaster]

@Uberi Can you check this PR ?

Really need it, at least for playing a sound or light up some LEDs when hotword is triggered :)

[palikar]

Hi @wibimaster ,

I am now a maintainer of the library too and will merge the PR soon. Can you, however, test the change by implementing some simple application using it. I've been using the code in the PR for a while now I don't see any weird behavior but I am not quite sure if it's not messing the time calculations somehow.

[wibimaster]

I'm using it, I cannot confirm there isn't any problem ; I'm using SPeechRecognition + Snowboy, and have some weird behavior like 100% CPU and lag on hotword detection when it runs from some minutes..
But I had this behaviors before implementing this PR

(CPU down to 50% after implementing #395)

[wassgha]

Any progress on this PR?