Switch to shiny container.

.travis.yml

@@ -1,7 +1,12 @@
+sudo: false
+
 language: cpp
 
-before_install:
+addons:
-  - sudo apt-get update -qq
+  apt:
-  - sudo apt-get install -y gcc-arm-none-eabi
+    packages:
+      - gcc-arm-none-eabi
 
-script: make
+script:
+  - cd firmware/
+  - make