Merged compatible code from no-statistics branch.
Merge branch 'master' of github.com:jtobey/bitcoin-abe into master-test
Merge
Move conn and cursor into SqlAbstraction.  Implement reconnect.
Fixes
Expose store._sql for upgrade.py.
Ported to SqlAbstraction-based DataStore, back to Abe29 (tested Abe37).
Log statement params at %r, not %s.
Bug fix: fix SQL flavour for upgrade.
Support *_approx for SQLite large integers.
Merge branch 'master-test' of github.com:bitcoin-abe/bitcoin-abe