Merge pull request #21 from gaddas/master

some small fixes
fix for SugarRecord default constructor
Merge remote-tracking branch 'origin/master'
Prevent crash when trying to open database

When the database has already been opened, don't try reopening it.
Instead, just return the current reference.
Merge pull request #23 from breber/crash

Prevent crash when trying to open database
added transaction support
Merge remote-tracking branch 'origin/master'
Only close the database when the Application terminates

I have run into some issues with older Android devices (Gingerbread)
crashing when trying to run nested queries. The database is closed
but even though we called openDB(). This change updates the queries
to just call db.getDB() when they need access to the DB, and leave
the closing of the database up to the Application when it terminates.
Merge pull request #24 from breber/close-issues

Only close the database when the Application terminates
added save in transaction with list parameter
reverted sugar activity