Optimize local speech output

[Bensge]

• MaryTTS output has too much padding at the end. It makes for a noticeably slow interaction.
• The beep sounds are too loud

[neumantm]

The relevant constant for the padding is here:

Amy/core/src/main/java/de/unistuttgart/iaas/amyassist/amy/core/speech/tts/TextToSpeechImpl.java

Line 47 in 84cf81b

private static final int DEFAULT_WAIT_TIME_AFTER_SPEECH = 1000;

[neumantm]

When making the padding any shorter Amy might hear her self. At least that was the case when implementing this padding. Someone should check that again with the new speech system.

[neumantm]

@MakinZeel You made the beep sounds. Can you make a slightly quieter version? And maybe don't let them end so abrupt, but fade them out over a fraction of a seconds or so.