New project structure based on submodules (added samples module)
Prepare to build Android modules under Travis
Simplify test for ANDROID_HOME
Provide custom build command to Travis
Do not gitignore JAR files, required for Gradle wrapper
Remove some irrelevant entries from gitignore
Move classes under correct project path
Move samples to new rx.android package
Merge pull request #43 from ReactiveX/submodules

New project structure based on submodules (added samples module)