Adjusted Connection::transaction to provide Connection instance by default instead of transaction instance

Fixes #3568: When the primary query sets `asArray`, it is not respected by the `via` relational query

fixes #422

fixed some issues with schema detection

issue #3520

verify issue #3473

This reverts commit 70b57766.

fixes #3252

also improved unit tests for querybuilder buildLikeCondition

fixes #2650