Make mic mute counting instead of boolean

====  Tech Notes ====
Mute was previously a simple boolean meaning that if two parts of the
code wanted to mute it it would unmute the mic as soon as the first of
the two pieces of code wanted to unmute.

For example tts output will mute the mic and unmute it when the audio
output is complete. During first start up of a mark-1 the enclosure
mutes the mic and expects it to be muted until the pairing is complete.
This doesn't work. The mic get's unmuted as soon as the first sentence
has been spoken.

This counts the number of times mute is called and will not unmute until
as many unmute calls has been made.

mycroft/client/speech/main.py

@@ -79,13 +79,11 @@ def handle_wake_up(event):
 
 
 def handle_mic_mute(event):
-    if not loop.is_muted():
-        loop.mute()
+    loop.mute()
 
 
 def handle_mic_unmute(event):
-    if loop.is_muted():
-        loop.unmute()
+    loop.unmute()
 
 
 def handle_paired(event):

mycroft/client/speech/mic.py

@@ -52,12 +52,17 @@ class MutableStream(object):
         self.muted = muted
         self.SAMPLE_WIDTH = pyaudio.get_sample_size(format)
         self.muted_buffer = b''.join([b'\x00' * self.SAMPLE_WIDTH])
+        self.mute_calls = 0
 
     def mute(self):
+        self.mute_calls = self.mute_calls + 1
         self.muted = True
 
     def unmute(self):
-        self.muted = False
+        self.mute_calls = self.mute_calls - 1
+        if self.mute_calls <= 0:
+            self.mute_calls = 0
+            self.muted = False
 
     def read(self, size):
         frames = collections.deque()
@@ -95,7 +100,13 @@ class MutableMicrophone(Microphone):
         Microphone.__init__(
             self, device_index=device_index, sample_rate=sample_rate,
             chunk_size=chunk_size)
-        self.muted = False
+
+    @property
+    def muted(self):
+        if self.stream:
+            return self.stream.muted
+        else:
+            return False
 
     def __enter__(self):
         assert self.stream is None, \
@@ -117,12 +128,10 @@ class MutableMicrophone(Microphone):
         self.audio.terminate()
 
     def mute(self):
-        self.muted = True
         if self.stream:
             self.stream.mute()
 
     def unmute(self):
-        self.muted = False
         if self.stream:
             self.stream.unmute()