Stable release

• Adds a new ExecAllIn method for working with IN query sqls.
• Adds a tag to identify primary keys using db_pk key.
• A better project structure

Stable release

• Updates PrimaryKey to use interface value that way we can use primary keys of any data type like uuid, string etc. instead of just bigint.
• Papergres is now go modules friendly.

Stable release

Merge pull request #9 from Paperchain/testcov

Removing unused code and improving coverage.