Travis clean up (#562)

Tidy Travis dependency installation

.travis.yml

@@ -1,40 +1,37 @@
 language: c
 
-cache: apt
-
-dist: xenial
-
-os:
-  - linux
-  - osx
-
-compiler:
-  - gcc
-  - clang
-
 matrix:
-  exclude:
-    - os: linux
-    - os: osx
   include:
     - os: linux
       compiler: gcc
+      cache: apt
+      dist: xenial
+
     - os: osx
       compiler: clang
 
-before_script:
-  - export CFLAGS="-Wall -Wextra -Werror"
+addons:
+  apt:
+    packages:
+      - libusb-1.0-0-dev
+      - libfftw3-dev
+      - dfu-util
+      - gcc-arm-none-eabi
+      - libnewlib-arm-none-eabi
+      - python-yaml
+
+  homebrew:
+    taps: PX4/homebrew-px4
+    packages:
+       - fftw
+       - gcc-arm-none-eabi
+       - dfu-util
 
 before_install:
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew tap PX4/homebrew-px4; fi
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install fftw gcc-arm-none-eabi dfu-util; fi
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then export PATH=/usr/local/bin:$PATH; fi
-    # Linux containers don't have access to the latest gcc-arm-none-eabi package
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then wget -O gcc-arm-none-eabi.tar.bz2 https://developer.arm.com/-/media/Files/downloads/gnu-rm/6-2017q2/gcc-arm-none-eabi-6-2017-q2-update-linux.tar.bz2; fi
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then tar xf gcc-arm-none-eabi.tar.bz2; fi
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then export PATH=$PATH:$PWD/gcc-arm-none-eabi-6-2017-q2-update/bin; fi
-  # For virtualenv(?) reasons we can't apt-get install python-yaml
-  - pip install PyYAML
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then pip install PyYAML; fi
+
+before_script:
+  - export CFLAGS="-Wall -Wextra -Werror"
 
 script:
   - mkdir host/build
@@ -56,10 +53,3 @@ script:
   - cd ../build-rad1o
   - cmake -DBOARD=RAD1O ..
   - make
-
-addons:
-  apt:
-    packages:
-      - libusb-1.0-0-dev
-      - libfftw3-dev
-      - dfu-util