Reworked return values so that you always get res, err plus sometimes previous_errors
Test for previous errors when using try_hosts
Test for previous errors when using try_hosts
Revert "Test for previous errors when using try_hosts"

This reverts commit 4e0e2a173966865c384043c4d42ad4f3d69d8ee3.
Fixed connect_to_host failing when no options passed, plus test
Fixed connect_to_host failing when no options passed, plus test
Revert "Fixed connect_to_host failing when no options passed, plus test"

This reverts commit e2978e4fca382834e26877c83d1ea2ea99dbf5e1.
Test for overriding connect options
Added sentinel to default command list
Only set connect_options if they exist, as the function call will fail on a nil value
Merge branch 'master' of github.com:pintsized/lua-resty-redis
Further documentation for return values