Install scipy now that it's required for some tests

The new 192kHz tests require scipy, but also other tests that worked
before, just because ffmpeg/avconv converted files automatically to
16 bits samples, but now, if the file format uses float samples,
we use 32 bit samples.

Author: antlarr

.travis.yml

@@ -8,7 +8,7 @@ before_install:
   - sudo add-apt-repository ppa:mc3man/trusty-media -y
   - sudo apt-get update --fix-missing
 install:
-  - sudo apt-get install -y ${CONVERTER} libopus-dev
+  - sudo apt-get install -y ${CONVERTER} libopus-dev python-scipy python3-scipy
 python:
   - "2.7"
   - "3.3"