Merge pull request go-pg#558 from go-pg/fix/dial-backoff

Replace dial backoff with dial testing

Merge pull request go-pg#557 from go-pg/feature/dial-errors-threshold…

…-backoff

Add DialErrorsThreshold and DialBackoff

orm: don't inline data if slice is empty

Merge pull request go-pg#556 from go-pg/feature/where-group

orm: add WhereGroup

Merge pull request go-pg#555 from go-pg/feature/bulk-updates

Support bulk updates

Merge pull request go-pg#553 from go-pg/fix/rework-pager

orm: rework pager

Merge pull request go-pg#552 from go-pg/fix/orm-query-getters

orm: add some getters to Query

Merge pull request go-pg#549 from go-pg/fix/index-sharing

orm: don't share slice between fields

Merge pull request go-pg#546 from go-pg/fix/is-zero-byte-array

Implement is zero for byte array

Merge pull request go-pg#540 from go-pg/fix/is-zero

Improve isZero