?readPreference=secondary doesn't actually work.

See #2 and https://jira.mongodb.org/browse/RUBY-547
Add --no-drop-tables option

This allows multiple MoSQL clients to run against different Mongo shards without
destroying the contents of the table(s) when each one is initialized.
Add a test_unit target.

Especially useful for running the unit tests without a mongod and/or
postgres available.
Fix parsing updates without _id in the update field.

Also, add a test case. closes #5.
Fix Gemfile.lock.
Fix deleting objects with BSON::ObjectId _id fields.

closes #8
MoSQL 0.1.1
Fix a bug with updates on objects with BSON::ObjectId's.

closes #9.
MoSQL 0.1.2
Make the default target run tests for Travis.
Add a .travis.yml
Merge branch 'master' of https://github.com/stripe/mosql into dot-syntax
Basic dot syntax support - need to cleanup _extra_props column and add tests