Create database directory if needed to ensure Android 4.4 compatibility

I just got my Nexus 5 with Android 4.4 KitKat and installed a Cordova application which uses the SQLitePlugin.

On application start, LogCat throws an SQLite Error:

```
11-04 12:10:31.767  15471-15508/? E/SQLiteLog﹕ (14) cannot open file at line 30191 of [00bb9c9ce4]
11-04 12:10:31.767  15471-15508/? E/SQLiteLog﹕ (14) os_unix.c:30191: (2) open(/data/data/com.mypackage.myapp/databases/Database-DB.db) -
11-04 12:10:31.777  15471-15508/? E/SQLiteDatabase﹕ Failed to open database '/data/data/com.mypackage.myapp/databases/Database-DB.db'.
    android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
```

Testing several things, I've figured out that Android (4.4) does not create the _databases_ directory automatically. My additions ensure that the directory exists before we try to open/create the database.