Fixed failing CI build.

Fixed stale build dependency version causing continuous builds to stall:

https://github.com/rgladwell/m2e-android/issues/274
Improved test error logging for continuous build.
Fixed failing tests.

Tests were failing due to change in the version numbers of Android
dependencies installed by the `maven-android-sdk-deployer`.

https://github.com/rgladwell/m2e-android/issues/274
Fixed failing test case.
Fix AndroidMavenPluginTestCase#buildAndroidProject

For some reason, the Android builders are not called anymore when
calling IWorkspace#build. This is fixed by calling all builders
manually.
Merge pull request #270 from WonderCsabo/fixBuildAndroidProject

Fix AndroidMavenPluginTestCase#buildAndroidProject
Removed unused test case.
Installing Android SDK with Travis

The Travis build now installs the Android SDK with the built-in option
in Travis. (http://docs.travis-ci.com/user/languages/android)
Use JDK8 in Travis

It has improved memory-management for example the whole PermGen space
has been replaced with the new MetaSpace. We thought maybe some OOM
causes our test to fail in Travis, so that's why i made this change,
but it did not help. This is still interesting, because it is a good
thing to run the build and the test on a newer VM.

https://github.com/rgladwell/m2e-android/issues/274
Update maven plugin versions

So they are working well even with JDK8. Precisely, the old version of
the findbugs plugin has issues with JDK8. Also added maven version
requirenment to the POM, so we can properly display newer versions with
versions:display-plugin-updates. Moreover, the build will fail if
someone tries to use a lower maven version.
Update build-tools in Travis

Old build-tools can brake the tests.

https://github.com/rgladwell/m2e-android/issues/274
Fix stalling usage statistics dialog

The dialog is also opened if there was no pingId saved to
~/.android/ddms.cfg. See
https://android.googlesource.com/platform/sdk/+/master/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/welcome/AdtStartup.java
line 84.
It is important to close this dialog, since it can hang the test due to
waiting for user interaction.

https://github.com/rgladwell/m2e-android/issues/274
Update build-tools in Travis Android install

https://github.com/rgladwell/m2e-android/issues/274
Switching to Docker-based Travis build system

https://github.com/rgladwell/m2e-android/issues/274
Quarantine failing test
Do not install preinstalled Android components on Travis

On Docker-based VMs, Travis has an issue
(https://github.com/travis-ci/travis-ci/issues/2848), it cannot update
already installed Android dependencies, and fails the build while doing
that. To work around this problem, we remove those dependencies from
the Travis script for now. We should readd them in the future, since
the list of preinstalled dependencies may change:
http://docs.travis-ci.com/user/languages/android/#Pre-installed-components
Merge pull request #283 from WonderCsabo/fix-ci-docker

Fix continous integration on Travis.
Fix ProjectImporter with default destination directory

If the destination directory is not set, the ProjectImporter will use
the artifact name as the project folder. But there was a problem with
calculating the destination in that case: relative path used instead of
absolute path.
Compatibility with android-maven-plugin-4

Since version 4.0.0 the android-maven-plugin uses the gradle / Android
Studio folder layout. This means AndroidManifest.xml is at
src/main/AndroidManifest.xml, res is at src/main/res and assets is at
src/main/assets by default. We already support non-ADT folder layout by
using Eclipse resource links to point to the actual resource. The only
thing this commit is changing that we are now reading default values
from the android-maven-plugin parameters, so we can link to the default
structure even if the user do not explicitely define these properties.

Related to #266.