Updating schedule rows working

src/org/osuosl/ocw/DataBaseHandler.java: Added methods to check if row exists in schedule or speakers table.

src/org/osuosl/ocw/Schedule.java: If event already exists in database it is updated otherwise it as added as a new row. Methods to check if row exists in schedule or speakers table. DataBaseHandler now instantiated in onCreate rather than every time a helper method is called. Code commented out to support just one day conference to match with current sample json.