Env variables in yaml config

Add support for .env variables in the yaml config. Closes #20 (closed). Also apply some minor fixes: #22 (closed)

config/for-docker.yaml

@@ -4,7 +4,7 @@ Audio:
     # force input file format, for example "alsa"
     file_format: "alsa"
     # optional?: audio codec format, for example "pcm_s32le"
-    sample_format:
+    sample_format: "pcm_s32le"
     # number of channels, for example 2
     channels: 2
     # optional: sampling rate, for example 44100.
@@ -14,7 +14,7 @@ Audio:
     # input file to listen to, can be a pcm device or a stream
     # for example "dsnoop:CARD=USB,DEV=0", "http://stream.freirad.at:8002/live.ogg", "AuRa_recording"
     # leave the input file blank for a cli selection of a pcm device
-    file: "default"
+    file: ${AUDIO_DEVICE}
     # optional: set to True if you want a virtual composite audio device
     # this will take the input_file and try to create a dsnoop pcm device
     virtual_device: False
@@ -31,12 +31,12 @@ Audio:
     # the file format, for example "flac" or "ogg"
     format: "flac"
     # where to store the recordings, if empty engine-recorder/audio/recordings/block is used
-    store_dir:
+    store_dir: "/var/audio/recordings/block"
 
 # Optional Rsync
 Sync:
   # set to true if you want to sync the content of audio/recordings/block to somewhere else
-  sync: True
+  sync: False
   # the destination where we sync to, this can be a remote location. If you chose a remote location
   # make sure that you supply a sshkey, otherwise the script will ask you for your password every
   # day