Test with Rails 4
fix dependancy version
add a minimal schema-dump extension

We just detect whether the PK is auto-increment or not and turn on and
off global-uid.  not perfect, but probably close enough
Merge remote-tracking branch 'origin/master' into ben/schema_dumper

Conflicts:
	global_uid.gemspec
checkpoint
Merge remote-tracking branch 'origin/bquorning/rails4' into ben/schema_dumper
upgrade to mysql2, fix tests
add test
only 2.0 and 2.1.1
send prepend
rewind/read -> .string
Merge pull request #18 from zendesk/ben/schema_dumper

Ben/schema dumper