prepared the 1.2 release
bumped version to 1.3-DEV
added Dariusz as an author
Add JoinFunctionFixer
feature #771 Add JoinFunctionFixer (keradus)

This PR was squashed before being merged into the 1.3-dev branch (closes #771).

Discussion
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Add JoinFunctionFixer

Implement #769

Commits
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ac6f1de Add JoinFunctionFixer
Make isCacheAvailable protected