add dudie-github-parent pom and change slf4j implementation

Release and snapshots will be deployed using the deployment strategy
defined in dudie-github-parent pom.

Replacing slf4j-itinerennes by slf4j-android:itinerennes.
Update maven-android-plugin version
Initialize readme
[travis] Enable Travis ci
[travis] android-7 sdk must be installed as it is the default target
[travis] resolve plugin dependencies while the emulator starts
[travis] add all android targets to matrix build
[travis] better matrix format
[travis] limit tests to older target and most used ones
Replace onebusaway-api with itinerennes-api
Use static itinerennes API
[readme] add documentation
ZipAlign APK even on snapshot build