updating Travis CI

.travis.yml

@@ -1,12 +1,19 @@
-language: c++
+language: python
+python:
+    - "2.7"
+
+# Cache PlatformIO packages using Travis CI container-based infrastructure
 sudo: false
-before_install:
-  - source <(curl -SLs https://raw.githubusercontent.com/adafruit/travis-ci-arduino/master/install.sh)
+cache:
+    directories:
+        - "~/.platformio"
+
+env:
+    - PLATFORMIO_CI_SRC=examples/delay/delay.ino
+    - PLATFORMIO_CI_SRC=examples/repeat/repeat.ino
+
 install:
-  - arduino
+    - pip install -U platformio
+
 script:
-  - build_main_platforms
-notifications:
-  email:
-    on_success: change
-    on_failure: change
+    - platformio ci --lib="." --board=uno