Enable Travis-CI

Try Travis-CI [1] as a continuous integration server. There is a CI
server for the project [2], but Travis is able to build pull requests
right after they were submitted.

[1] http://travis-ci.org/
[2] http://ci.dahanne.net/job/m2e-android_master/
Enable Xvfb and run UI tests

[1] http://about.travis-ci.org/docs/user/gui-and-headless-browsers/
Tweak default Travis CI's build lifecycle for Maven

- Don't do anything during 'install' step;
- Running 'mvn install' will compile sources, run unit and integration
  tests as defined by Maven's lifecycle.
Merge pull request #120 from manandbytes/travis-ci

Travis CI Enabled
Updated hacking instructions with latest dependency versions and remove
redundant steps.
Fixed the output classes folder to be platform neutral (was using
Unix-specific folder separator character).
upgraded com.github.github:site-maven-plugin to 0.7 and using an OAuth token to authenticate
Fixed "un-recognised maven-android project type" error when working with apklib as dependencies (#139)
[task #104] Add: integration tests to verify that Android Libraries 
isn't exported and that Maven Dependencies classpath container isn't
exported for Android libraries.
[task #104] Add: only export Maven classpath container for non-library
projects, and never export Android Libraries container to ensure correct
transitive dependencies added to APK build.
Upgraded minimum ADT version to latest version to include new, required
Android Private Libraries classpath container.
Fixed NPE caused by method returning null.
Fixed error in tests caused by old version of ADT that does not support
private libraries container classpath.
Upgrade Tycho version to latest.
Added support for running integration tests on Mac OS.
Fixed Travis build so that it now downloads and install Android SDK.
Removed unworking filter commands from Travis SDK update command.
Fixed failing Travis build caused by installation of ia32-libs happening after calls to SDK.
Fixed failing Travis build - apt-get install requires initial aot-get update.
Fixed failing Travis build - incorrect install directory.