android pre-populated databases; support deleting databases on API < 16

Working on issue #10 -- Android part ready for review.  Tested on Android emulator for 4.4 (API 19) and 2.3 (API 10).  Also implemented deleting databases on Android API < 16 from discussion in #86.

This is my first experience with Android as well as my first pull request; critiques encouraged.
Working with streams in Java is a pain in the ass, but the standard idiom which you should use is this:

```java
InputStream in = null;

try {
  inputStream = whatever;
  // do a bunch of stuff;
} catch (IOException e) {
  // log the exception, do something smart
} finally  {
  if (inputStream != null) {
    try {
        inputStream.close();
    } catch (IOException e) {
      // yeah, you have to catch the exception twice. Java is marvelous
    }
  }
}


```