Removes submodules

Prequisite for merging maven branch.
Squashes ecgreb:maven branch into a single commit for rebase.

* Updates submodules
* Adds parent and module POMs; adds compiled native dependencies.
* Adds script to install local maven dependencies.
* Removes gradle build config
* Removes submodules
* Remove submodule folders
* Remove dependency installation script
* Moves resources folder to module root.
* Moves AndroidManifest to module root.
* Moves vtm assets into module root.
* Renames vtm native libs.
* Massive pom updates.
* Ignore generated files for apklibs and IntelliJ.
* Fix test error due to execution order.
* Move android-maven-plugin to last stable release
* Collapses project into single maven module (removes parent).
* Moves junit to first in dependency list (above Android SDK).
* Updates Google Play Services to version 15.0.0
* POM cleanup
* Update README.md
Moves TestViewport into new test root.
Update README.md

Change vtm repo url to mapzen fork.
Update README.md

Adds Android SDK 4.3 to setup instructions (required by Robolectric)
Merge pull request #45 from mapzen/maven

Maven